FRONTISPIECE.

Map of India.

The black shading indicates the Himalayan and Palearctic portions to the North and, in India, areas above the dividing line of tropical and sub-tropical India, usually above 2,000 feet. The dotted black line to the North is the political boundary, inclusive of Cashmir and Sikkim. The red lines and lettering indicate the faunal zones of Tropical India as described in the Section on Geographical Distribution below. The dotted lines dividing the West Coast indicate probable sub-regions and correspond to the Palghat and Goa gaps in the Ghauts. Sub-tropical faunal zones are not indicated.

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INDIAN INSECT LIFE

A MANUAL OF THE INSECTS OF THE PLAINS

(TROPICAL INDIA)

BY

FT: MAXWELL-LEFROY, M.A., F.E.S., F.Z.S.,

Entomologist , Imperial Department of Agriculture for India; Author of “ Indian Insect Pests , ” etc

Assisted by

F. M. HOWLETT, B.A., F.E.S.,

Second Entomologist, Imperial Department of Agriculture for India

[ Published under the Authority of the Government of India]

AGRICULTURAL RESEARCH INSTITUTE, PUSA

CALCUTTA & SIMLA THACKER, SPINK & CO W. THACKER & CO., 2, Creed Lane, London

PRINTED BY

THACKER, SPINK AND COMPANY,

CALCUTTA.

“ Plus je connais les peuples, Plus j* aime les insectes.”

ACKNOWLEDGMENTS.

The sections on Mallopliaga , Diptera , Cimicidce and A noplura have been prepared by Mr. Howlett, and the Interlude on Insects and Flowers by Mr. I. H. Burkill, Reporter on Economic Products. Illus¬ trations marked I. M.N. are from the stock of drawings accumulated by my predecessors in the Indian Museum, and used in Indian Museum Notes. Those marked F. M. H. have been drawn by Mr. Howlett, who has directed the preparation of those illustrating the sections he has written. Where not otherwise acknowledged, all the plates and illustrations are the work of the Artist staff of this Institute under my or Mr. Howlett’s direction ; it may be pointed out that these artists are wholly Natives of India, trained in Art Schools of this country ; it is needless to emphasise how much the book owes to their beautiful work as also to the enterprise of the publishers, who have done the work of reproducing all the illustrations in this country. I wish to specially express my appreciation of the work of Mr. Slater of the Calcutta Phototype Company in the printing of the Colour Plates, carried out under very trying climatic conditions and for the first time in this country.

As regards the text, it is, where not stated to be a quotation, orig¬ inal ; 1 have acknowledged every direct source of information. The book owes something to the work of my staff, since it is based on the Pusa collections to which they have contributed specimens and observ¬ ations. I have acknowledged this where I can. The volume is largely a product of my spare time and scanty holidays ; such a volume has been so much required that I have felt that even an imperfect one was better than none. Six years ago the work of this section commenced and if the book contains imperfections, the critic will recog¬ nise that it is based on collections, observations and reference books that have been accumulated only in that short time ; I shall be glad if those who see omissions or errors will point them out, as it may be that a better volume will be built up on this basis, when the study of Indian Entomology is further advanced. I may also emphasise the fact that where little is said, little is known and the blanks in the book are

VI

ACKNOWLEDGMENTS.

designedly prominent to emphasise the enormous scope there is for work. I trust also that the volume may be a real stepping-stone to better things and may help those who are advancing our knowledge of the insect life of India.

Pcsa : ]

June , 1909. |

H. M. L.

CONTENTS

Page.

Acknowledgments

Classification adopted

Introduction . . . . . . . . . . 1

Diagnosis . . . . . . . , . . 1

Zoological position . . . . . . . . 2

Instinct and Habit . . . . . . . . 2

Classification . . . . . . . . 10

Number of species . . . . . . . . 14

Nomenclature . , . . . , . . 15

Identification . . . . . . . . . . 15

Entomology in India . . . . . . . . 17

Zoo-geographical Divisions . . . . , . . . 20

Food and Habitat . . . . . . . . 27

Insects and Man . . . . . . . . 35

Aptera . . . . . . . . . . 43

Orthoptera . . . . . . . . . . 47

Where Insects live . . . . . . . . 54

Cosmopolitan Insects . . . . . . . . 62

Deceptive Colouring . . . . . . . . 90

Attraction to light . . „ . . . . . 106

Neuroptera . . . . . . . . . . 108

Gregariousness . , . . . . . . 123

Aquatic Insects . . . . . . . . 131

Relative Duration of Life . . . . . , . . 140

Hymenoptera . . . . . . . . . . 161

Galls . . . . . . . . 167

Size of Insects . . . . . . . . . . 169

Sex . . . . . - . . . . 188

Insects and Flowers . . . . . . . . 222

COLEOPTERA . . . . . . . . . . 234

Myrmecophilous Insects . . . . . . . . 268

Insects as Food .. .. .. .. 276

Lepidoptera . . . . . . . . . . 397

Migration . . . . . . . . . . 419

Emergence from the Cocoon . . . . . . 481

Silk .. .. .. .. ..485

How Insects protect themselves . . . . . . 521

viii contents.

Thysanoptera . . . . . . . . . . 542

Diptera . . . . . . . . . . . . 545

Blood-sucking Insects . . . . . . . . 659

Rhynchota . . . . . . . . . . . . 665

Song in Insects . . . . . - . , . . 720

Index of Plants . . . . . . . . . . 765

General Index . . . . . . . . . . 773

SCHEME OF CLASSIFICATION.

The following is a complete list of the families into which insects are divided, tabulated under orders. The families in heavy type, thus Forfioulidse should be familiar ; those in ordinary type, thus Campodeidse, are of smaller importance but occur in India : those in italics, thus Smynthuridce, are not yet known to occur in India.

APTERA	Page. 43
Thysanura.
Camped eidu , .	43
Japygidse	44
Maehilid*	44
Lepismidse	45
COLLRMBOLA.
Lipuridae	46
Poduridse	46
Smynthuridce . Neelidce.
ORTHOPTERA	47
0URSORIA.
Forficulidse . .	49
Hemimeridw
Blattidee	56
Mantidee	64
Phasmidse	71
Saltatoria.
Aoridiidse . .	74
Locustidse . .	91
Gryllidee	97
NEUROPTERA	108
PSEUDONEUROPTERA.
Mallophaga . .	110
Ernbiidse	112
Termitidse	115
Psocidee	121
■ Amphibiotica.
PerHdse	124

	Page.
Odonata	125
Ephemeridae . .	137
Planipennia.
Sialidae	143
Panorpidae . .	145
■Hemerobiidee	146
Trichoptera	157
HYMENOPTERA	161
SESSILI VENTRES	164
Gephidoe
Siricidse	164
Tenthredinidee	164
Parasitica	165
Cy rn pi die	166
Proctotrypidse	168
Dryinidse	170
Chalcidee	172
Ichneumonidre	177
Braoonidee	178
Stephaniidse	180
Megalyridce
Evaniidse	180
Pelecinidce.
Trigonalidse	181
Tubulifera.
Chrysidse	182
Aculeata, Fossores.
Mutillidse	185
Thynnidse	192
Scoliidse	192

X

SCHEME OP CLASSIFICATION.

		Page.
Sapygidce Pompilidae		194
Sphegidse . .	. .	199
Diploptera.
Eumenidse . .	• •	210
Yespidae Masaridee.		213
Anthophila.
Colletidae	. .	216
Apidae	. .	217
Heterogyna.
Pormicidae		224
COLEOPTERA		234
Lamellicornia.		241
Passalidae		242
Lucanidae		243
Scarabaeidae		245
Melolonthidae		252
Adephaga.
Gicindelidae		259
Carabidae		262
Paussidae		266
Rbysodidae . . Amphizoidce.		272
Pelobiidce. Dytiscidae . .		272
Haliplidae		279
Gyrinidae		280
Polymorpha.		281
Hydrophilidae Platypsyllidce. Leptinidce.		283
Silphidae		286
Scydmaenidae		287
Gnostidce. Pselaphidae . .		287
StaphyliDidae Sphceriidce.		288
Trichopterygidae Hydroscaphidce.		291
Corylophidae		292
Scaphididae . . Synteliidce.		292
Histeridae . .		292
Phalacridae . .	, #	294
Nitidulidae . .	, ,	295
Cossypbodidae	• .	297

Page.

Colydidae . . . . 298

Lathridiidae . . . . 298

Trogositidae . . 299

Monotomidae . . 300

Cucujidae . . . . 300

Cryptophagidae . . 302

Helotidae . . . . 302

Thorcitidae . . . . 302

Erotylidae . . . . 302

Mycetophagidae . . 303

Coecinellidae . . 303

Endomycliidae . . 309

Mycetceidce.

A dimer idee.

Dermestidse. . . . 310

Byrrhidae .. .. 311

Cyathoceridce.

Georyssidae . . . . 312

Heteroceridae . . . . 312

I Parnidae . . . . 313

Derodontidce.

Cioidae . . . . 313

Sphindidce.

Bostrichidae . . 313

Ptinidae . . . . 317

Malacodermata.

Malacodermidae 319

Cleridae . . . . 325

Lymexylonidae . . 327

Rhagophthalmidae 327

Dascillidae . . . . 327

Rhipiceridae . . . . 327

Sternoxi.

Buprestidae. . . . 328

Throscidae . . . . 331

Eucnemidae . . . . 331

Cerophytidce.

Elateridse . . . . 332

j Dicronychidae . . 334

Plastoceridoe .

Cebrionidae . . . . 334

Heteromera.

Tenebrionidae . . 335

Cistelidae . . . . 339

Lagriidae . . . . 340

Othniidae . . . . 340

Aegialitidce.

Monommidae . . . . 340

SCHEME OF CLASSIFICATION.

XI

Page.

Nilionidce.

Pythid® . . . . 341

Melandryid® . . . . 341

Pyrockroid® . . . . 341

Antkicid® . . . . 342

Oedemeridse . . 342

Mordellid® . . . . 343

Cantharidse. . . . 343

TrictenotomidsB . . 347

Phytophaga.

Bmchidee . . . . 349

Ohrysomelidee . . 351

Oerambycidee . . 368

Rhynchophora.

Anthribid® . . . . 379

OureulionidsB . . 380

Brenthid® . . . . 392

Seolytid® . . . . 393

Agly cyder idee.

Proterhinidce .

Stylopid® . . . . 395

LEPIDOPTERA . . 397

Rhopalgoera . . 401

Nymphalidse . . 404

Memeobiid® . . 415

Pieridse . . . . 416

Papilionidee . . 421

Lyceenidse . . . . 423

Hesperiidse . , 429

Heterocera . . 432

Syntomidae . . 433

Arctiidse . . . . 434

Agaristid® . . 439

Moctuidse . . 440

Pterotliysanid® . . . 458

Lyman true m . . 459

Hypsidas . . 462

Sphingidse . . 464

Oymatopkorid® . . 469

B'upterotidse . . 470

Notodontid® . . 471

Geometrid® . . 473

Saturniidse . . 475

Bombyetdee . . 483

Brahmeid® . . . . 490

Ceratocampidoe.

TJraniid® . . . . 490

Psychidae . , . . 491

Heterogynidw . Arbelidee		Page. 493
Argymtypidce. R a tar did®	# •	494
Oossidae	• •	494
Lasiocampid®	. .	496
Endromidoe. Chrysopolomidw. Perophoridce . Meg atopy gidw.. Limacodid®		498
Dalceridw . Neocastniid®		501
Castniidoe. Euschemonidce. Microlepidoptera		501
Zyg®nid®		502
Callidulid®		504
Drepanid® . .		^04
Thyridid®		505
Pyralidse	• .	505
Orneodid®		526
Pterophoridse		526
Sesiid®		528
Tortricidae		529
Tineidse		531
Protolepidoptera. Hepiaiid®		541
Micropterygidcs . 1 THYSAHOPTERA		542
Terebrantia. Aeolotkripid®		544
Tbripid®		544
Tubulifera. P hi® o t imp id®		544
! DIPTERA		545
1 Orthorhapha Nemocera	554
Psychodidse		557
CMronomidee		560
OulioidsB		564
! Dixid®		576
Blepharocerid®		576
Tipulidee	♦ *	578
Ceoidomyiidse		580
Mycetophilid®		583
Bibionid®	• *	586
Simuliide©	♦ t	587

Xll

SCHEME OF CLASSIFICATION.

Orphnephilidae

Rhyphidae

Orthorhapha Brachycera. Stratiomyidae Leptidae Tabanidae.

Cyrtidae

Nemestrinidae

Bombyliidae

Apioceridae

Scenopinidae

Therevidae

Mydaidae

Asilidae

Empidae

Dolichopodidae

Pboridae

Lonchopteridcz

Cyclorhapha Aschiza. Syrphidae Platypezidae Pipunculidae

Cyclorhapha Schizophora.

Acalyptrate Muscoids Calyptrate Muscoids Oestridae

PUPIPARA.

Hippoboscidae.

Streblidce

Nycteribiidae

Braulidae

SlPHONAPTERA.

Pulicidae

RHYNCHOTA

Heteroptera

Gymnocerata

PentatomidaB

Ooreidae	Page, 679
Berytidoe	685
Lygaeidae . .	685
Pyrrhocoridae	690
Tingidae	692
Aradidae	693
Hebridae	693
Hydrometridae	694
Henicocephalidae	696
Phymatidae	696
Saldidae	696
Reduviidae . .	697
Aepophilidce Ceratocombidae	702
Oimicidae . .	702
Anthocoridae	705
Polyctenidae	705
Oapsidae	705
Cryptocerata	709
Pelogonidae . .	709
Nepidae	710
Naucoridae . .	712
Belostomidas	713
Notonectidae	715
Oorixidae . .	716
Homoptera	717
Oicadidae	718
Fulgoridae	722
Membracidae	729
Cercopidae . a	732
Jassidae	734
Phytophthires	740
Psyllidae	742
Aphidae	743
Aleurodidae. .	748
Cocci dee	752
Pediculid^i	762

Page.

589

589

589

591

592

595

596

597

600

600

601

602

602

605

606

608

609

610

612

612

614

617

641

651

654

656

657

657

665

667

667

668

INDIAN INSECT LIFE.

INTRODUCTION.

The insects are tracheate, hexapodons arthropoda, with a distinct head bearing antennae, with a great degree of complexity in their devel¬ opment during which a series of moults are undergone, culminating in the appearance of functional generative organs and wings ; in the higher forms, the development is sharply divided into three distinct periods, the last of which is marked by the inactivity of the organism as a whole and the complete reorganisation undergone by the tissues ; they are essentially air-breathing animals, living on land, but some have become adapted to living in fresh water. The number of jointed legs separates them clearly from other tracheate Arthropods, just as the metamorpho¬ sis, the possession of wings and the form and the number of segments does. They are regarded as being most closely related to Peripatus of all present forms of life, and undoubtedly represent a great branch of the tree of life whose development equals, if not excels, that of any other branch. In numbers, in species, in all but one form of mentality, the insects are the dominant form of life on the land at the present time, but the limitations put on them are of such a nature that their dominance must remain within bounds and, unless man be removed, cannot be actual and entire.

Insects are of all sizes from inch long to over six inches ; their numbers are incalculable, the number of their species being put at about three millions ; their lives are very short, (a week,) up to as long as over ten years, though rarely actually exceeding more than three years, and being in the larger number limited to an active life of less than three months. On the surface of the earth, as in fresh water, they are found wherever nutriment is available, even in the bodies of warm-blooded animals and man ; over the three-fourths of the earth’s surface covered by the sea they are practically non-existent, a very small number of

IIL 1

2

INTRODUCTION.

species being able to support life near, in or on the sea. Their position in the animal world is shown in the table : —

Protozoa.

Porifera (Sponges).

Ccelenterata (Anemones, etc.).

Ctenophora (Jelly-fish, etc.).

Echinodermata (Sea-urchins and starfish).

Vermes (Worms).

POLYZOA.

Arthropod a. — Crustacea (Lobsters, etc.)

Prototracheata (Peripatus).

Myriapoda (Centipedes and millipedes).

Insecta (Insects).

Arachnida (spiders, mites, scorpions, etc.).

Mollusc a (Snails, etc.).

Brachiopoda.

Chordata. — Hemichordata.

Tunicata.

Cephalochordata.

Craniata. Cyclostomata.

Pisces (Fish).

Amphibia (Frogs).

Reptilia (Snakes, etc.).

Aves (Birds).

Mammalia (Mammals).

Economically, the insects are the most important group of animals next to the Mammals, Birds and Fishes. Their activities affect man daily, either from the nature and extent of their injuries to economically valuable plants, or to domestic animals, or to wild animals, or to stored produce, or from their value in yielding useful products ; or from the part they play in the economy of nature, in fertilising flowers, in scaveng¬ ing and cleansing the earth, in rendering waste matter available as plant food, in preserving the condition of the soil and in furnishing food for birds and fishes.

Instinct and Habit. — What is the life of an insect ? In what way can it be compared with our own or with the life, for instance, of any of

INSTINCT AND HABIT.

3

the animals familiar to ns ? No answer can be easily given, for the senses, the instincts, the modes of expression of insects are so totally diverse from onr own that there is scarcely any point of contact. In the case of mammals, of birds and to some extent of reptiles, we have in the eyes, in the features and in the movements, a clue to their feelings, to the emotions that sway them, to the motives that guide their actions ; in insects we have none, and the great index of insect feeling, the antenna, has no counterpart in higher animals, and conveys nothing to our un¬ informed brains. We can judge then only from the movements of in¬ sects, from their actions, and this is so extraordinarily meagre a clue that it is not surprising that even the greatest familiarity with the life of an insect inspires no feeling that one has to do with a live organism having feelings and passions, having motives and a will, but suggests that one has before one a beautiful machine, tuned to respond mechanically to certain outside stimuli, to answer to particular influences and to behave in all things as a perfect mechanical structure ; even the highest, the social insects and the fossorial wasps, inspire no other feelings, give one no sense of any relations between the individual insects but those mechanical ones concerned with daily life, and leave one with the conviction that the mentality of the higher animals is wholly absent, that no smallest trace of the emotions, of the will, of the thought processes of ourselves or other mammals, have any part in the lives of insects. Yet there are events in the lives of insects which, for a brief moment, impress us with the conviction that individuality, emotion and feeling may play their part ; and though we see this exceedingly seldom, the few suggestive phenomena may be sufficient to warrant the assump¬ tion that in ways we cannot comprehend, in channels that are beyond our ken, the living active insect is in touch with every other living insect in its environment, by mental and physical processes that make no out¬ ward sign, that may proceed independently of any external sense organ that we can see or study and which possibly pass from mind to mind with no outward physical action or movement ; what occurs when bees swarm, when locusts swarm, when the white ants emerge from the nest, when a stray bee from one nest enters another and is promptly attacked and killed ? Are these wholly due to reflex actions and mechanical instincts, or are they the product of an individual will and mind in each and every insect ; a locust swarm may be the product of a blind impulse

4

INTRODUCTION.

sweeping over a host of insects just as a blind impulse ranges through a crowd of human beings by means which are certainly not normal or in daily use ; the emergence of the flying ants suggests a similar blind im¬ pulse, an unreasoned compliance with fixed instincts like the blowing up of a boiler when certain physical conditions are arrived at ; do the ants have councils and decide when the nest shall be moved to a new locality, or is it simply the common impulse of the community, simultaneously born of the same reaction to certain physical conditions ? So wide apart are our senses from those of insects, so divergent are our means of expression, and the mechanism of our bodies, that no answer can be given to these questions ; we cannot establish any connection with the individuality of insects, we can get no common basis of thought, no pos¬ sible means whereby even to 4 4 tame ’ ’ them or to get even so little response to our efforts as a tame bird will give. To us, the closest study of large numbers of the same species reveals no individuality, nothing but a mechanical sameness in a large number ; perhaps this is because we cannot get near enough ; to the ordinary man, sheep are sheep and while differing in small points are alike ; to the shepherd they are as individual as human beings and have a similar mental individuality ; I have never seen that this was the case with insects, and none that have been kept in activity, fed, cared for and most closely observed, have shown more than very small traces of individual mentality or even responded to advances. (That this is not the view every author takes is evident from the writings of naturalists who state that butterflies in particular become tame and welcome their captor’s visits ; but these cases are not sufficiently numerous or well authenticated to be valid.) It is not unreasonable to consider that, in freedom and living under natural surroundings, nearly every insect is solitary ; an individual insect appears to take no notice of any other, save such as it may prey on or parasitise ; it goes about its business of food-getting and the like, it makes no smallest sign that it is aware of the existence of any other insect, and so far as can be judged from its actions, is leading an abso¬ lutely and wholly solitary life ; there are exceptions, of course, but very few ; the social insects are apparent exceptions, but even there it is extremely doubtful how far individuals are not isolated ; they work to¬ gether it is true, but in a manner that suggests two machines under the same controlling conditions, not two sentient reasoning organisms acting

INSTINCT AND HABIT.

5

in agreement due to any mental process. The same is true of termites, of locusts, of all the social insects which exhibit such wonderful phenomena. The Pyrrhocorid Iphita limbata is gregarious and lives in colonies on the bark of trees ; is there any communication, any individuality, any mental process other than a blind reaction to some outside stimulus, under which all alike find that a particular spot is perhaps the warmest or the best suited for some such reason ? There are other exceptions which are perhaps more valuable ; the courtship of butterflies is a beautiful thing, suggesting two perfectly happy beings enjoying to the full the delights of each other’s company and the perfect happiness of the crowning moment of life; there is no doubt of their being aware of each other’s presence, but the cold thought creeps in that it is after all a mechanical process, born of peculiar instincts, with nothing more c ‘ living ’ ’ than the reaction of two parts of an engine. The dances of flies and other small flying insects suggests mentality, social insects thoroughly enjoy¬ ing each other’s company and the extraordinary pleasure that huifran beings find in concerted movement ; it is possible that we can compare insects with ourselves in this respect, but the balance -of evidence is certainly against it ; one comes inevitably to the feeling that insects are a supreme expression of living matter adapted and co-ordinated to physical conditons, responding perfectly to mechanical stimuli, without mind or mental processes as we know them and as we can see them in birds and mammals ; they are the highest expression of life as evolved by natural processes, perfect machines without emotions. No thinking man questions the existence in higher mammals of mind-processes akin to our own if far lower, of some slight evidences of that higher mentality we call the soul, and which we hold to be the essential life, for which the objective life and the material body is but a case. No one would credit an insect with such forms of mentality, and the most sympathetic student of insect life has not advocated such a point of view. An insect is a living machine, responding to definite physical stimuli, with well- defined and very complex instincts, which are mechanical forms of mental action and take their origin in outward conditions. Were they possessed of higher forms of mentality, such as reason, judgment, voli¬ tion and the like, no one can say what might be the course of the world’s history ; a combination of the red ants (( Ecophylla smaragdina) could probably drive human beings out of India and render the continent

6

INTRODUCTION.

uninhabitable to any form of life inimical to them ; an organised cam¬ paign of the common black ant ( Camponotus compressus) could effect a great deal and human methods of warfare would require to be revo¬ lutionised to deal with it.

In practice we can consider insects as consisting of organisms whose actions will be definite responses to stimuli, whose movements and acti¬ vities will, under the same circumstances, be the same ; given the same conditions, all the individuals of a species will behave alike with only very minute variations which we have great difficulty in seeing. If we find that one of a species has a certain definite life history we are safe in concluding that under the same circumstances all of that species will have the same life history and that with a given departure from normal circumstances all will behave alike ; when we have worked out the life history and habits of one of a species, we can confidently assert that all will have that life history, with only small variations due to changed conditions ; a leaf- eating caterpillar that feeds on maize leaf in Behar, might quite well feed on juari leaf in Gujarat where maize is not grown, but it would not, for instance, become a borer in the Punjab and a pre¬ daceous caterpillar in Madras. We may, therefore, treat a species as an individual, and not expect to find different habits in different indivi¬ duals of the same species. At the same time we must allow for the variation consequent on changed conditions ; the limit of adaptation to changed conditions is a very variable one ; as an example, many cater¬ pillars have but a very few foodplants and cannot live on others ; a few have many, and the Gram Caterpillar ( Chloridea obsoleta) feeds on the seeds of gram, the heads of opium poppy, the heads of bajra or sunflower and a variety of other plants ; in the United States it is the boll worm feeding on the seed of cotton and accordingly has slightly different habits ; in this there is a certain amount of variation in habits due to changed foodplants. Such cases are frequent, but the variety of habits lies with¬ in perfectly clear and definite limits, varying slightly from species to species. On the above reasoning, a species is definable not only on structural characters but also on its habits and mode of life ; if we look on a species as composed of individuals reacting mechanically to stimuli, with a limited play of adaptation to changing conditions, habits and mode of life are as much specific characters as is structure ; if our struc¬ tural distinctions are sound, they will be in agreement with habits and

INSTINCT AND HABIT.

7

life history, and the one aspect is as important as the other. Our know¬ ledge of structure is far greater than our familiarity with the habits of insects, but the latter will increase. It is all important for the student to grasp clearly from the beginning that a “ species” is a distinct indivi¬ dual as much in habits, mode of life and all details of its life as in its colour, form, or any structural detail on which it is declared to be a distinct species. We are here far more concerned with the living insect as a living reality than with the dead shell on which its place in the insect world is determined and on which it is described and named ; the characters of the living insect, its method of flight, its walk, its feeding habits, its expressive antennal movements, all the details of its daily life are of as great value as its structure and are of far greater importance to us in these pages ; a realisation of this fact and an understanding of what a species really is, must come to every student sooner or later if he is to become anything more than a systematist and a classifier of insects on purely structural details; the individuality of a species is as much discernable in the field as in the museum and takes in every detail of the insects life. For that reason, we have considered this abstruse point at some length and we would emphasize the point of view given, though it may seem at first sight an incorrect one. Variations in habits between two members of a species are so small that what we find out of a single individual, applies to every individual of that species with due allow¬ ance for variable conditions ; a very large part of our work lies in deter¬ mining how far different conditions modify the habits of an insect and the limits of this variation are becoming clearly established; if, therefore, the habits of an insect are observed in Peshawar, we know that the individuals of that species will have in the main the same habits at Madras, that we can predict the variations likely to be found, and that if we knew enough we could absolutely say how far they would differ.

We may touch very lightly upon one more point ; whence come the instincts and beautiful habits of our present-day insects ? According to the accepted theories of evolution, insects, like other animals, are descended from more primitive forms of life which existed in earlier geologic periods; if we imagine the primitive types of insects being evolved and multiplying, and supposing them to feed on the abundant decaying vegetable matter, we shall get a great development of simpler forms scattered over large areas of land, and living in a diversity of physi-

8

INTRODUCTION.

cal conditions ; remembering their less specialised and complex structure, we can see that the influence of altered conditions might produce great variations in structure, in habits, in life history ; the pressure of com¬ petition would arise, supposing there were fewer checks ; (what checks there may have been is doubtful but both parasitic and predaceous insects, as well probably as insectivorous birds arose later and these are now the main checks) ; some, from feeding on decaying vegetable matter, might come to feed on decaying animal matter, with a consequent change of habits, of structure, of senses, possibly of life history ; others might find growing plants provided an ample supply of food and their descendants gradually get modified to suit these circumstances ; in time we can imagine some becoming predaceous, the descendants perhaps of insects that fed on dead insects ; we can still see the stages between land and aquatic insects, and it requires little imagination to picture the necessary gradations from an insect feeding on decaying leaves by a riverside, to one that entered the river water and found its food there. Given a plastic structure capable of modification, granted grow¬ ing competition and a free unoccupied field, one can readily see how, in earlier ages, the various groups may have arisen ; with the alter¬ ing conditions of successive geologic periods, with the evolution of higher plants and animals, with alterations of climate and natural con¬ ditions, one can realise how the diversity of forms of insect life would be evolved. That this has occurred with other forms of life one can read ; that the steps cannot be traced so clearly in insects is due to the imperfection of the geological record, insects being small, soft and not so fitted for preservation as are bones or shells. Granting that in previous ages this occurred, and seeing the present dominance of insect life on the earth and in fresh water, it is easy to see that the competition might be so severe that more and more complex structures, instincts and habits might be evolved leading steadily away from plasticity to more and more fixed and unalterable types ; the more primitive and simple insect feeding on decaying leaves, having simple biting mouth- parts, laying eggs in the ground, requiring no special colouring or pro¬ tective devices disappeared ; predaceous insects require more complex trophi ; quick flight necessitates better wings and a more consolidated thorax ; protection from birds implies protective attitudes, colouring or form, and may require possibly the nocturnal habit, which implies

INSTINCT AND HABIT.

9

better sense organs ; all crystallises down to a specialised form with fixed instincts. So too, for instance, with parasitic insects, the new habits imply new structure, the petiolate body and the ovipositor are developed to lay the eggs, and with the necessity for flying by day comes warning colouring and unpleasant taste or odorous glands, since birds are developed also and are taking to eating insects. Consider a Sphegid catching live insects, paralysing them, laying them up for its young ; imagine the development of such forms, the gradual acquirement of more and more perfect structures, and with them of more and more fixed instincts till we have the perfect insect, with intensely modified life history, with fixed and complex structure and with nearly all plasticity and power of change gone.

This is the point I wish to make ; we are now at a stage in the earth’s history when competition has produced an amazingly complex number of forms of insect life, which adapted themselves to every condition of life but that in saltwater, which have, by the im¬ provement of more and more perfect forms, become increasingly complex, specialised and fixed ; variation, except in each special direction, makes for destruction ; from the increasing competition plasticity is gone, the forms are fixed and unalterable, and what may once have been forms of active mentality implying some choice, some volition, are now fixed instincts, crystallised reflex and, possibly, voluntary actions. It is true that all are not equally complex or special¬ ised, but I believe it to be true that almost all, simple or complex, are fixed, are no longer alterable except so minutely and so slowly that we can no longer see it. It is questionable whether there is any form with which we could people a part of the earth, say an island, that was abso¬ lutely devoid now of insect life, and in which we could see this process of differentiation and specialisation take place, but could we find such a form, could we give it the same free field and let it multiply and increase, we should get a similar differentiation and an ultimate specialisation of equally fixed forms.

The student may read this for himself at greater length in text¬ books of palaeontology, geology and evolution ; he must realise it if he is to grasp the meaning and origin of the forms and habits of insects ; and in no other group is it so marked as in insects ; when we consider the abundance of forms of life in the insect world, their absolutely

10

INTRODUCTION.

universal occurrence on land and in fresh water , the extraordinary variety in habits, food and ways of life, as compared with any other group or with all groups together, we can see that in no other class in the animal world is competition so keen, are instincts and habits so fixed, is the whole of life for each species so unalterable and delicate. Insects have lived, have dominated the earth, have become what we see them by carrying to an extreme the principle of adaptation to circumstances, of making the most of natural conditions ; man has become what he is, because he has carried to an extreme the principle of adapting natural conditions to himself while only adapting himself to them to a limited extent ; the two classes dominate the land, and when man cannot alter the conditions to make life permanently bearable, insects can adapt themselves and do. But in the process man has developed one form of mentality implied in the terms free-will, choice, volition, while insects have become perfect mechanical structures reacting in a definite way to natural forces and stimuli, their lives ruled by fixed and most perfect “ instincts.”

It is not my intention to give the impression that instincts are absolutely fixed but only that they are fixed as compared with the plasti¬ city of earlier insects and as compared, say, with man. There is a certain latitude still, more in some groups than in others, but even in them not much and in the most specialised probably very little. I imagine that such simple forms as Machilis are fixed in their simple habits as compared with a Sphegid fixed in complex habits, but to both there is a certain small latitude within which they can still alter. The instincts of a polyphagous caterpillar such as Chloridea obsoleta are pro¬ bably much less fixed and specialised than are the instincts of the caterpillar of Scirpophaga aurif.ua , for instance, and in each case possibly their degree of specialisation, low or high, makes for success, success being purely the ability to get food and lay eggs freely. Some are- successful because they are fixed in delicate mechanical instincts, notably the insect- stinging wasps ; others are successful because they can adapt themselves still to a limited variation of circumstances, such as food, temperature, etc., and they are still to some extent plastic. But it is a very limited plasticity, little akin to the plasticity of the earlier forms from wdiich our present insect life has arisen.

Classification.— When insects were first studied in some detail,

CLASSIFICATION.

11

the complexity of the increasing number of recorded species led to a system of grouping, say, the beetles under one title, the moths and butter¬ flies under another, and so on, the insects most obviously similar being put into one group chiefly as a matter of convenience. As the subject grew, the morphological characters of the collected insects were utilised to an increasing extent, and the more the number of known insects increased, the more minute and detailed was this classification. When the evolution theory was accepted, it was evident that every scrap of available information would be required to give data on which to make a natural grouping of insects ; what was the origin of insects ? from what had they developed ? how far had different insects remained for a long period in the same condition, and how far was the evolution either continuing still or had it been continuous up to the recent past ? These were the questions to be answered, and the answer is embodied in the present-day system of classification which is believed to be so far natural that it conforms, as far as possible, to the actual developments of insects during the earth’s history and does represent actual relation¬ ships. On these terms all the members of one group are more closely interrelated than each one is to any other insect not in that group.

In making this classification, there are practically three main sources of evidence: (1) the morphology of the insect in all its stages ; (2) the processes of embryological and post-embryological development ; (3) the evidence of fossil and extinct insects.

In the beginning, the first alone was utilised, and it is still the main source of information; at first superficial characters were used, then more detailed ones such as the structure of the trophi, finally the fuller evidence afforded by all parts of all stages is being utilised, though this is by no means near completion. The second has been utilised, but not to a great extent. The third has been utilised as far as it is available, but the geological record is scanty, and what there is, is very imperfectly available as yet. There is a great bulk of literature on this question, and it is impossible to more closely enter into the subject here. How little is really known can be gauged from the great changes made in the classi¬ fication of Ileterocera, for instance, as well as from the fact that ento¬ mologists have arrived at no definite conclusions which are generally accepted. The most diverse views prevail, and there is no standard classi¬ fication that is or can be universally employed even if it be admittedly

12

INTRODUCTION

not academically accurate, but sufficiently so for practical purposes. As knowledge grows, as groups are revised, new views are expressed, new systems adopted. This would matter little if there were, for instance, agreement as to one unit, say the family, if it could be decided that Coleoptera. for instance, are a homogeneous group of say 80 families ; unfortunately this is impossible at present. Actually, insects are prima¬ rily divided or have been divided into primary divisions called orders. Thus Coleoptera are a distinct enough order ; when we go below this, we should have a definite number of sub- orders, each containing a definite number of families ; the sub-family is the next division containing a number of genera. Unfortunately superfamilies, legions, cohorts, tribes, etc., have been used, and it is rare to find all authorities on an order or sub- order using the same classification.

In this volume, we propose to follow the Fauna of India, in using the terms order, sub-order, family, sub-family, division, genus, species, but as classification is not our main object, we can largely simplify the system actually used in the Fauna.

Entomologists have adopted the family as the unit of classification trying to group insects first into divisions which must have had a common ancestor ; on this basis we get nearly 300 families, each of which represents a fairly homogeneous assemblage, derived from one branch of the tree ; the difficulty is greater when we try to group these families to find the main limbs of our tree or to find how many separate limbs we should have, derived each from some lower form of life ; for instance, Lepidoptera area very homogeneous order, the families derived from one branch ; Orthoptera on the other hand are by no means uniform, and so far as can be seen, the order instead of coming from one branch may really come from three ; none the less, in the absence of sufficient data to find really how many branches there are, the order Orthoptera as here adopted is a very convenient one. Our nine orders are constituted then with a regard both to truth and con¬ venience and a student should think in terms of families, grouping these families into aggregates which we may call sub-orders and orders.

In practice we have to utilise a conventional system that embodies as much truth as possible and which is reasonable for working purposes.

Of the nine orders we adopt here, seven are generally accepted by entomologists, but there is great divergence of views over the Neurop -

CLASSIFICATION,

13

tera. With regard to this, the following tables show the terms used by other authors : —

Orders.	Sub-orders.	Families.	Smith’s orders.	Wood worth’s orders.
		'Mallophaga.	(	Embiidge.*	Mallophaga.*	1
		Pseudoneuroptera		Termitidas	Isoptera	> Corrodentia.
		(	Psocidae ...	Corrodentia.*	\
	j		i	( Perlidas	Plecoptera.*
Neuroptera	>	Amphibiotica ..		Odonata	Odonata.	Odonata.
		*1	[ Epheneridae .	Ephemerida ...	Ephemerida.
			1	| Sialidge	Platyptera*
		Planipennia		: Panorpidge ...	Mecoptera.*
			i	f Hemerobiidse	Neuroptera.*	* Neuroptera.
		.Trichoptera	Phryganeidas	Trichoptera.*

We believe the most logical and workable system of insect classi¬ fication to be the following : —

1. Aptera.

2. Forficulld/r.

3. BLATTIDiE.

4. Orthoptera (5 families).

5. TERMITIDiE.

6. Mallophaga.

7. Pseudoneuroptera. (Embiidae, Psocidee).

8. Neuroptera Amphibiotica.

9. Neuroptera Planipennia.

10. Trichoptera.

11. Hymenoptera? Phytophaga. (Sessiliventres).

12. „ Parasitica.

13. „ Tubulifera.

14. „ Aculeata.

15. COLEOPTERA.

16. Lepidoptera.

17. Diptera, Orthorhapha.

18. „ Cyclorhapha.

19. Siphonaptera.

20. Rbynchota, Heteroptera,

14

INTRODUCTION.

21. Rhynchota, Homoptera,

22. Phytophthires.

23. Anopleura.

24. Thysanoptera.

It is, however, impossible to express accurately the relationship of insects by adopting any one sub-division of equal value throughout, and the student may be warned against getting to attach too much importance to any classification systems except as working conven¬ tions which have as much regard to truth as circumstances will allow.

What systems of classification we adopt is, in the present state of confusion, immaterial ; the Fauna covers only parts of four orders and we can there adopt the system in use ; beyond that we must unfortu¬ nately anticipate the “ Fauna.” The system adopted is the following; it is as near to Sharp’s insects as possible, and we have contrasted it with the system in use in America as a guide to the student who wishes to refer also to American literature. W e may remark that classification is not an end in itself but is the means to an end ; with so vast and com¬ plex a subject, it is imperative that we should be able to classify, to fix the position of an insect with regard to its fellows, simply for ease of working. Our main object being the observation of living insects as they affect man, classificaton in this case becomes necessary to enable us to record and collate our observations ; for this reason we aim at a simple system, on which we can arrange our collections, file our notes and, by working with one system, follow each other’s work at once with¬ out having to readjust our ideas or bother more than is necessary with the way our things are arranged. The insects in one collection are arranged exactly as they are in another ; a worker from a distance can take up work in Pusa without mastering a fresh system, and whether our classification be correct or not, it is, and must be, the standard and will be, we hope, with small modifications, the standard in India for many years.

Number of Species. — Blanford in 1881 published a numerical enumeration of the known Fauna of India (J. A. S. B., p. 263). He in¬ cludes Beluchistan, Kashmir, the Himalayas, Nepal, Sikkim, Bhutan, Assam, British Burma? Tennasserim, Ceylon, Andamans, Nicobars,

NOMENCLATURE.

15

which is practically the area now covered by the “Fauna of British

We reproduce his	figures : —
Orthoptera	350 (?)	1,700
Neuroptera	350	400
Hymenoptera	850	3,600
Coleoptera	4,780	6,000
Lepidoptera	4,620	10,000
Diptera	500 (?)	1,000
Rhynchota	650	3,000
Total	12,100	29,700

giving also an enumeration of our own based on the available figures. Thus the Fauna of India and Hampson’s later papers enumerate about 8,000 moths, there are about 1,500 butterflies, and we estimate 500 Tineids, etc. Mr. Distant has already enumerated 2,500 Rhynchota, and we anticipate 400 more with 100 Coccidse.

Nomenclature.

Could we divide all known insects into, say, 300 families of roughly 1,000 species each, and group these systematically, our nomenclature would be a simple matter.

As we have explained above, the general object is to make families the basis of classification ; but we have in this volume to steer a middle course between the really accurate classification of the pure svstematist, which changes as knowledge grows, and the practical point of view of those for whom we write ; we cannot keep remodelling our arrange¬ ment and nomenclature. Odonata, for instance, may be a sub-order composed of say seven families ; for us and for all field entomologists it is practically a family.

Whenever possible, family names end in — idee, sub-family names in — inw , and the names of tribes or sub-divisions of families in — ini ; the student must, however, remember that sub-family names frequently end in —ides ; and tribes in — ines. It is to be regretted that no uniform system can be introduced, and that were we to rigidly adhere to some system in this volume, the student would be puzzled when reading foreign text-books or literature.

Identification of Specimens. — Insects are known by names, nomi¬ nally of Latin or Greek form, given to them by the entomologist

16

INTRODUCTION.

who first describes them. That is, every distinct species of insect that ha*s been described or accurately figured is designated by the specific name assigned to it by its first describer. The problem then is, with living or preserved insects on one side, and the mass of descriptions or figures on the other, to correlate the two.

Only working entomologists ever realise the immense labour in¬ volved in this work, except in the case of the fauna of a locality such as England where the insects have been studied very closely, where there are ample books, and reference collections. Where one has either a description of every species of insect of a country or a good reference collection, identification is a matter of so much comparison, but where as in India, the only handbooks contain descriptions only of part of the known insects, or where there are no handbooks at all, only scattered descriptions, and where there are no reference collections and access to the National Collections at the British Museum is impossible, the actual identification of an insect is not an easy matter and is not, as a rule, even possible in India. The question must remain so until there are complete handbooks such as the Fauna of India, which are kept up-to-date, and also complete reference collections of Indian insects, accurately named ; progress to these is being slowly made, but very slowly indeed.

Actually if an insect belonging to one of the families described in the Fauna of India is sent in for identification, it is examined, referred to some division of its family, worked out with the generic key in the volume and compared with the descriptions in the volume ; if it exactly agrees with the description of a particular species, it is believed to be that species and is, if possible, compared with a specimen that has been identified by a specialist in that family. If it agrees with no species in the volume, it may be either a species described since the volume was prepared, or a species known from another country but not from India, or a new species ; to determine this requires an expert knowledge of the family, a complete literature of the family and a reference collection. On the other hand, if a beetle, for instance, is sent in, it is examined, referred to its family, and compared with any accurately named speci¬ mens of its kind which are available ; if it agrees with none of them it must be sent to a specialist in that family who has the literature, the reference collection, and, after years of work on that particular family,

ENTOMOLOGY IN INDIA.

17

the requisite special knowledge. If proper attention was devoted to entomology in England, all specimens could be sent to the National Collection at the British Musuem and there compared ; at present this is not possible, and we are largely dependent on the kindness of workers in Europe and the United States.

It can be seen that the accurate identification of an insect is no easy matter in every case ; in many cases it means months of waiting, and even years, as there are no workers for a large number of groups. As an accurate identification is necessary before publishing matter about any insect, this question is one of great importance ; a large number of insects have been accurately identified and can be seen in the Pusa Collections ; every assistance will be given in identifying insects, but the reader must realise what it means and be prepared to do the only thing he can to help, namely, to always send enough good specimens to allow of some being sent on to Europe, if the species is one that cannot be named from the Pusa Collection. This matter is discussed here because requests are constantly received for the name of an insect of which perhaps one mangled specimen is sent, and surprise is expressed because the identification is not immediately forthcoming. (See also Indian Insect Pests, page 57.)

Entomology in India.— -This volume has been compiled primarily for the use of students of entomology in India and for those interested in the subject. A few words as to the present state of the subject in India will not be out of place.

Entomology, as a subject, occupies the whole time of one section of the Agricultural Research Institute, Pusa, and in this Institute alone there are three Entomologists with English University qualifications, and a staff of trained native workers. In connection with this Institute, there are a limited number of entomological assistants employed by the Agricultural Departments of each province for purely agricultural work and simple teaching. Whilst the ultimate object of work at Pusa is mainly agricultural and directed to useful practical ends, the work must rest on a scientific basis, and the collection, study, and classi¬ fication of all insects of the agricultural areas of India is a necessary part of the activities of the staff. It is open to any worker in India to visit Pusa or to write there for advice or assistance, which will be freely given.

2

IIL

18

INTRODUCTION.

Our aim is to be in touch with every worker in India and to invite co¬ operation and mutual help. Elementary and advanced teaching in entomology is also given at Pusa and at no other place in India at the present time.

For many years, the Indian Museum, Calcutta, was the centre of entomological work, where a special staff was devoted to this subject, including the economic aspect. At the present time, the economic work has been transferred to Pusa, and systematic entomology takes its place as one branch of the systematic zoology which forms the work of one section of the Musuem.

Collections of insects are preserved there, are constantly added to and are sent to specialists to Europe, just as the Pusa collections are. There is a large exhibit collection open to the public and the reference collections, while not open to the public, are generally available to work¬ ers in entomology.

Forest entomology is solely dealt with in the Forest Research Institute, Dehra Dun, by the Imperial Forest Zoologist and his staff, and all enquiries regarding insects injurious to forests are referred there. The study of insects injurious to tea is the work of the Entomologist to the Indian Tea Association stationed at Hilika, Assam.

Apart from minor and inconsiderable collections in Provincial Museums, the only other public collections exist at the rooms of the Bombay Natural History Society ; members of this society refer specimens to the Committee who, if the Society5 s collection and library cannot furnish the required information, refer them to either of the above Indian Institutions or to Entomologists in Europe.

Excepting private wmrkers who own private collections, there are no other centres of entomological activity in this country.

Publications dealing with entomology in its different aspects are issued as follows : The Imperial Agricultural Department issues, from Pusa, the “ Agricultural Journal of India, ?? in which are contained articles and notes relating solely to those insects injurious to crops or to those of economic value. Other and similar work is issued in bulletins ; the. more scientific or lengthy work is issued in memoirs and purely popular and useful information as leaflets.

ENTOMOLOGY IN INDIA.

19

The Imperial Forest Research Institute publishes information relative to Forest Entomology in “ Forest Records and Memoirs/’ and some has appeared in the pages of the “ Indian Forester.” “ The Bulletins of the Tea Association ” contain the bulk of the work on insects injurious to tea, supplementary to the volume on Diseases and Pests of the Tea Plant by Watt and Mann. The Indian Museum, in “ Indian Museum Records ” and “ Memoirs of the Indian Museum,” issues articles mainly on systematic entomology but also bionomic work.

The “ Journal of the Bombay Natural History Society ” is the recog¬ nised medium for most purely systematic work and for some bionomic work ; the papers in this Journal are of extreme value and must be consulted. We have referred below to the more important papers. The Journal of the Asiatic Society of Bengal contain also papers on general entomology and on systematic work.

This exhausts the present publications dealing with the various aspects of this subject in India ; occasional papers on systematic entomology appear in the proceedings of learned Societies in England, Europe, the United States. A summary of these is contained in the Annual Report of the Board of Scientific Advice in India, as is a summary of all entomological work and publications in India.

It is necessary to mention one further publication no longer in exist¬ ence. For over fifteen years, “ Indian Museum Notes” was issued from the Indian Museum, Calcutta, and contained papers, notes, etc., dealing with economic and systematic entomology. We have made constant reference to it below and practically all information contained in it, dealing with the insects of the plains, is abstracted or referred to here, or is amplified in Indian Insect Pests. The best feature of this publica¬ tion was its beautiful photogravure plates ; the originals of many of these are here reproduced as text figures. Sets of this publication are still available at Pusa, and complete sets can be consulted in most official or public libraries in India.

With the exception of the Bombay and Asiatic Societies, the above publications are issued by Government and copies of most of them are available to serious workers. All can be seen also in most public libraries, and the published work in entomology is generally available. It is impossible to refer here to other literature ; the reader will see

20

INTRODUCTION.

below from how many sources we have drawn the published informa¬ tion of past years and these scattered papers are often very difficult to see. The best entomological libraries known to me in India are that of the Indian Museum, Calcutta, and of the Pusa Research Institute.

Of books dealing only with Indian Entomology, the Fauna of India is the only systematic one of real value now. It covers Aculeate Hymen- optera (2 vols.), a small part of Coleoptera (2 vols.), nearly the whole of Lepidoptera (6 vols.), Rhynchota to the end of Jassidse (4 vols.). Progress with this is being steadily made and the student should ascer¬ tain what volumes have since been issued. They are the standard guides to the systematic entomology of India, Burmah and Ceylon and are essential in the arrangement and identification of species. West¬ wood’s Cabinet of Oriental Entomology is with Donovan’s “ Insects of India,” remarkable chiefly for beautiful plates in colour of many striking Indian insects, mainly butterflies, moths, large beetles and Fulgorids. It is the only book of its kind but is of little value at the present day except (in the words of Westwood), “that, by finding its way to the table of the Indian drawing room, it may gain additional converts to the study of a science full of curiosity and awaken an interest in the objects of pursuit, thus supplying an engaging occupation to our Indian friends.”

A very short introduction to entomology is given in ‘ ‘ Indian Insect Pests,” which also treats of insects injurious to agriculture. It is the only general book on pure entomology relating solely to India published recently (1906), and contains short instructions regarding necessary apparatus, methods, etc. We assume every reader to have as much general knowledge as is included in the first part of that volume and in the second appendix.

Zoo-Geographical Divisions.— British India is not a distinct zoo- geographical area, and it is necessary to define very carefully the faunal zone that is dealt with in this volume. The “ Fauna of India’ ’ series deals with the Fauna of the Indian Empire and Ceylon, i.e., Himalaya, Hindustan, Assam, Burmah, Ceylon, regardless of faunal zones, and we endeavour here to indicate the zoo-geographical status of this region.

In the first place, we wish to make clear that a fundamental point is elevation ; starting from the plains of North India at an elevation of,

200»GE0GRAPHICAL DIVISIONS.

21

say, 1,600 feet and going steadily up the Himalayas to say. 10,000 feet, one passes from, through and into three distinct life-zones, which we may call tropical, subtropical and temperate ; the tropical extends to 2,000 feet elevation ; it is marked by one period yearly of intense dry heat or a limited season of moist weather ; the subtropical covers 2,000 feet to between 5,000 and 6,000 feet and is marked by a greater humidity, a more even and less intense temperature, a less limited period of rainfall ; the temperate extends above about 6,000 feet. To accurately define the limits of the subtropical zone would require much elaborate detail ; it commences for instance at an elevation of about 500 feet at the foot of the Eastern Himalayas, at about 2,000 feet at the foot of the Western Himalayas ; in the Milgiris it commences at about 2,500 feet on the Mysore plateau side but runs down to well under 1,000 feet on the Western Ghaut side ; a large part of the Deccan above 1,000 feet is tropical; the Western Ghauts from 600 to 2,000 feet and over are subtropical, and in this case the dry tropical area (as at Poona and Nasik) is at a greater elevation than the moist subtropical belt. The zone is of course not definable merely on elevation ; it is the moister more agreeable climate produced by the abun¬ dant rainfall falling on the slopes of moderate elevation which run up from the level plains to the Himalayas or to the various ranges of hills ; it is a zone of varied vegetation, often forest or dense jungle ; it is the zone in which tea, coffee, rubber, and similar crops are grown, and it is, in India, a belt along the hills, running up the valleys, as well as more or less isolated patches on the hill ranges of Central India, the Deccan and South India. The student can get some idea of it from the 2,000 feet elevation line on Eliott’s meteorological atlas of India. The fauna of the subtropical zone is far more varied than that of the tropical zone or of the temperate zone and is quite distinct.

There are some prominent features of the tropical and subtropical faunae which may be very briefly discussed here. We omit any discus¬ sion of the temperate fauna as, except in South India, it is certainly not “ Indian ” but is holarctic or Indo-Chinese. The subtropical fauna is far more varied than the tropical ; the number of species that can find food and can support existence in the extremely varied vegetation and moist equable climate of the former is far greater than those that can endure the intense dry heat and more limited vegetation of the latter.

22

INTRODUCTION.

In addition to this, which is true of nearly every family of insects, there are families which are confined to the subtropical region, or which im¬ mensely predominate there as compared with these families in the plains, and there are also families which occur far more abundantly in the tropical plains. The Phasmidce , Siricidce , Tenthredinidce , Sialidce, Panorpidce, Passalidce, Lucanidce, Simuliidce, Aradidce , Phymatidce, Sesiidce , Zygcenidce are practically confined to the moist forested lower hill slopes ; the Rhopalocera are characteristic of the subtropical region, especially the Nymphalidce and Papilionidce ; the Cicadidce, Tipulidce , Mycetophilidce, Locustidce , Dynast idee. Cetoniidce , Erotylidce , Endomychidce , Boslrichidce, Scolytidce are found abundantly in the subtropical, rarely in the tropical areas ; Chrysomelidce, Buprestidce, Capsidce. Syrphidce occur in both but in immense profusion only in the former ; Limacodidce and Pliryganeidoe stand out conspicuously in the same way. On the other hand, the Acridiidce, Carabidce , Dytiscidce , Hydrophilidce, Gyrinidce, Tenebrionidce, Myrmeleonince , Ascalaphince , Scaraboeidce are far more abundant in the plains, though occurring also in the lower hills. Allow¬ ing for the fundamental excess of species in the subtropical region owing to its varied flora, the other large families are more proportionately represented in both areas. We would suggest also that the varied sur¬ face fauna of the plains is less marked a feature of the subtropical region, possibly because the surface soil offers protection from heat not required in the hills and because the usually dense perpetual vegetation of the hills produces a fauna centering more round the bushes and low vegetation (see below u Where Insects Live ” under Forficulidce).

This fundamental distinction is of the very greatest importance, and unless it is fully realised and clearly kept in mind, any conception of the faunal zones must be imperfect. W e sharply mark off the fauna of the plains of India (usually below 2,000 feet) from that of the forested slopes of the hills and from that of the upper hills ; and, in this volume, we deal only with the tropical zone except where the number of species occurring in India is stated when we mean British India exclusive of the temperate upper Himalayas.

India is placed by Beddard (Zoogeography 1895) in the Oriental Region as the “ Indian ” subregion ; Ceylon is distinct as a subregion and is taken to include part of South India. The Himalayas, inclusive of Kashmir, Nepal, Sikkim, Bhutan, are not part of the Indian subregion

ZOO-GEOGRAPHICAL DIVISIONS*

23

at all, being holarctic, and we take the dividing line to be at about 6,000 feet. The extreme North-West of India is also not strictly “ Indian 55 but is holarctic. Burmah, we exclude, as being Malayan and Indo- Chinese, and the hills of Assam are strictly Indo-Chinese in part. “ In¬ dia ?? proper then does not include these areas at all and it must be clear¬ ly borne in mind that in these pages we do not use India in the sense that the “ Fauna of India 55 does : the term “ British India ” is used throughout this volume for the political India covered by the Fauna ; the term “ India ?? includes tropical and subtropical India, i.e.t up to about 6,000 feet ; “ subtropical India ” denotes the moist forested slopes of the hills usually between 2,000 and 6,000 feet ; “ tropical

India ” or “ the plains ” means the great stretches of India lying between sea-level and about 2,000 feet, usually not forested and extending from Tinnevelly in the South to Bawai Pindi in the North, from the border of Sind and Baluchistan in the West to the Assam and Surma valleys in the East. It is the insects of this area that are discussed in these pages and for one insect in this area there are at least five in “ subtropical India. ”

The frontispiece illustrates the divisions of tropical India according to fauna so far as we are able to tentatively delimit them ; the faunal zones of subtropical India are not indicated. In considering this question fully, the factors to be considered are (1) the physical features of the country ;

(2) the geological formation composing it ; (3) its climate ; and (4) its flora. The first three probably affect insects in much the same way as they affect plants, and we may take the flora as the basis of our divisions ; Sir J. D. Hooker, in his sketch of the flora of British India, divides the whole area into nine provinces as follows

(1) Eastern Himalayas.— Sikkim to Mishmi mountains in Upper

Assam.

(2) Western Himalayas — -Kumaun to Chitral.

(3) Indus Plain.— Punjab, Sind, Kajputana, west of the Araval-

li range and the Jumna river, Cutch and Gujarat (to the Tapti).

(4) Gangetie Plain.— From the Aravalli Hills and the Jumna

river to Bengal, the Sundarbans, the plains of Assam, the low country of Orissa north of the Mahanadi.

24

INTRODUCTION.

There are three distinct sub-provinces ; the dry upper area, the United Provinces and Behar ; the lower humid area, the Assam plain, Lower Bengal and Orissa ; and the Sundarbans.

(5) Malabar. — The Western Ghauts from the Tapti river to

Cape Comorin ; the Konkan, Kanara, Malabar, Cochin, Travancore, Laccadive Islands. This is better termed the West Coast.

(6) The Deccan. — The high plateau lying between the Eastern

and Western Ghauts, south of the Gangetic and Indus plains ; the Coromandel Coast on the East Coast from the Mahanadi to Cape Comorin is included as a sub¬ province.

(7) Ceylon and the Maidive Islands.

(8) Burmah.

(9) The Malay Peninsula.

With the last three, as with the first two, we have no concern here. If on the basis of the above divisions we omit subtropical forest hill areas, and we take into account the influences on the fauna of these neighbouring areas, we shall get divisions as follows : — -

(1) The Indus Plain.

(2) Desert India.

(3) Central India, West.

(4) Gangetic Plain, West,

(5) Gangetic Plain, East.

(6) Sundarbans.

(7) Central India, East.

(8) Deccan.

(9) West Coast.

(10) Coromandel Coast.

1. The Indus Plain has a fauna containing many holarctic forms. The winter is cold, the hot weather is dry and intense and these two sea¬ sons are well marked.

2. Desert India is similar, but with a peculiar fauna and flora, owing to the arid conditions.

ZOO- GEOGRAPHICAL DIVISIONS.

25

3. Central India , West. — An area of greater rainfall, a more definite period of humidity and less alternation of day and night temperature.

4. Gangetic Plain, West. — Well marked winter with moderate cold and rain, dry hot weather and moist rainy weather. Immigrants from the Himalayas for the cold weather.

5. Gangetic Plain, East. — No well-marked dry hot weather, the humidity higher in the cold weather and hot weather. Immigrants from the Himalayas and other hills for the cold weather and insect activity more general in the hot weather ; there is a marked Malayan element. (A feature of this area is the flooding that occurs over large stretches of land; the influence this exerts on the fauna may be a very marked one.)

6. Sundarbans. — Doubtfully distinct. Little alternation of

temperature or humidity. Peculiar flora. Strong Malayan element.

7. Central India, East. — Well-marked dry hot weather when insect activity is suspended, followed by a prolonged moist warm period. Fewer insects hibernate than in the regions North and West.

8. Deccan. — Well-marked seasons, the dry hot weather following a marked cold weather, when hibernation sets in.

9. West Coast. — The fauna is influenced by the neighbouring sub¬ tropical region of permanent forests and high humidity which produce a very large fauna equalled only by the lower slopes of the hills in Assam and the Eastern Himalayas. No hibernation in the plains below ghauts. Many Ceylonese forms.

10. Coromandel Coast. — Less well marked seasons to the Deccan, and a smaller flora to the West Coast. A large proportion of Ceylonese forms.

We may roughly indicate the separate faunal zones into which we would divide British India as a whole exclusive of Burmah and Ceylon: —

1. Indus Plain. — Tropical.

2. Himalaya, West.— Western Himalayas above 6,000 feet, inclu¬ ding Kashmir, Nepal and Kumaon. Holarctic.

3. Sub-Himalaya, West. — -Lower slopes of Western Himalayas 2,000 to 6,000 feet. Subtropical forest fauna.

4. Desert India. — Tropical.

5. Central India , West. — -Tropical.

26

INTRODUCTION.

6. Central India , West, Hills. — -Subtropical.

7. Gangetic Plain, West. — Tropical.

8. Gangetic Plain, East. — Tropical.

9. Sub-Himalaya, East. — Lower slopes of Eastern Himalayas 700 to 5,000 feet. Subtropical.

10. Himalaya, East. — -Eastern Himalayas above 5,000 feet. Sikkim to Mishmi Mountains. Holarctic.

11. Assamia. — Hills of Assam and Assam- Bur mah border, in¬ clusive of Khasi hills, above 6,000 feet. Indo-Chinese.

12. Sub- Assamia. — Lower slopes of Assam hills, 500 to 5,000 feet. Subtropical with strong Malayan affinities.

13. Sundarbans. — Tropical.

14. Central India, East, Hills above 500 to 800 feet. Subtropical.

15. Central India, East, Plains. — Tropical.

16. Deccan. — Tropical.

17. West Coast, Plains . — Tropical.

18. Western Ghauts. — Hills up to 6,000 feet. Subtropical. This is probably divisible into three ; (a) Surat to Londa-Goa gap ; (b) Goa gap to Palghat gap with the Nilgiris, Coorg, Mysore Hills ; (c) South of Palghat gap, including Travancore, Pulneys, etc.

19. South India Hills. — Hills of West Coast and South India above 6,000 feet. The fauna of this zone is not sufficiently known, as apart from the fauna below 6,000 feet, for this division to be more than a doubtful one.

20. Coromandel Coast. — Tropical.

21. Eastern Ghauts. — Subtropical.

Classing these zones under elevation and climate we get : —

Temperate.	Subtropical.	Tropical.
Himalaya, West	Sub-Himalaya, West	Indus Plain. Desert India.
	Central India, West, Hills	Central India, West.
,, East	Sub-Himalaya, East	Gangetic Plain, West.
Assamia	Sub Assamia	„ ,, East. Sundarbans.
	Central India East, Hills ...	Central India, East.
	Western Ghauts	Deccan. West Coast.
South India Hills	Eastern Ghauts	Coromandel Coast.

FOOD AND HABITAT*

27

( H.OL ARCTIC*)

Himalaya West.

Baluchistan.

Afghanistan.

(Scheme of In¬ dian Region.)

(Indo-Chinese.)

Assamia. Himalaya, East. Burmah Hills.

Indus Plain.

Desert India.

Central India, West, Gangetic Plain, West.

-Cent ml India, East-

West Coast. Western Ghauts. South India Hills./ Coromandel Coast. Eastern Ghauts.

Ceylon.

Sub-Himalaya, East. Sub-Assamia.

Gangetic Plain, East. Sundarbans.

Burmah Plains." Malayia.

(Singhalese.)

(Malayan.)

Food and Habitat.

Insects live in a great diversity of ways, but it is possible to roughly classify these into groups ; this classification is of considerable value to the student in placing his insect ; for instance, a tree- boring insect will be a member of' one of a small number of families, and it will often assist in placing an insect to look up the families which have a particular habit i,et> it is useful to classify insects according to food and habitat, as well

as by structure and genealogy. For this purpose we tabulate below the principal families that live in distinct ways, using food and habitat together as the basis of our classification.

c

I.— LAND INSECTS. <J A. Herbivorous.

L Live in Fruits.

2. ,, on Seeds.

3. „ ■ L Flowers.

4. Leaf and Stem

Miners

5. Leaf and Stem

Suckers.

\ 6. Leaf and Stem

Eaters.

7. Gall Makers.

8. Tree Borers.

9. Stem Borers.

10. Boot Eaters.

11. Root Borers.

12. Root Suckers.

28

introduction.

"13. Parasites, Inter¬

nal of Vertebrates. 14. Parasites, Exter-

16. Predators, Sting¬ ing.

I.— LAND INSECTS ^

17. Predators, Biting and Sucking.

—contd.

'18. Scavengers, Animal Matter.

19. Scavengers, Dead

C. Scavengers. Wood.

20. Scavengers, Vege¬ table Matter.

21. Household Insects.

II.— SALT WATER INSECTS.

III. — FRESH WATER INSECTS.

IV. — MYRMECOPHILOUS INSECTS.

1. Fruit Insects. — The Trypetidce are conspicuous, as are such Tortricids as the Codlin Moth (Carpocapsa) and Tineidce. Noctuids and Curculionids are found. In all cases it is the larvae that live thus ; Tenthredinidce are rarely known. Some large moths ( Ophideres ) live on fruit juice. We exclude all “ Scavengers ” in decaying fruits, of course, referring only to fruits on plants.

2. Seed Eating Insects. — Many insects feed habitually on seeds while ripening ; Bruchidce, Scolytidce , Tortricidce, Tineidce, Pterophoridoe (. Exelastis , SpJienarches), Noctuidce (Chloridea, E arias), Pyralidce being typical examples ; the Lycaenid ( Virachola isocrates) is an exceptional case. We omit all insects living on harvested seeds, classing them as Scavengers or household insects.

3. Flower Insects. — Forficulidce eat pollen, Masaridce and Apidce collect pollen. Fossores collect pollen, or feed on nectar. Pkala- cridce (larvae), Nitidulidce (larvae and adults), Melyridce (adults), Lam - pyridce (adults), Mordellidce (adults), Curculionidce (adults), Melolon- thidce (adults), Cantharidce (adults) feed on pollen or flowers. Most moths and butterflies and many flies, especially Anthomyiidce , Syrphidce and Bombyliidce, feed on nectar. Tineidce, P ter ophor idee, Cecidomyiidce , Thysanoptera , Tingidce also live in flowers, as larvae or nymphs.

FOOD AND HABITAT.

29

4. Leaf and Stem Miners.—1 The Hispids and Halticids among Chrysomelids, and many Tineids mine under the epidermis of green leaves and green stems. Exceptional Micropterygids, Buprestids (Trachys), and Acalyptrate Muscids are also recorded.

5. Leaf and Stem Suckers. — The Thy sampler a, the whole of the Homoptera and Phytophthires, as well as most of the species of the fol¬ lowing families of Hemiptera live by sucking the sap of green parts of plants : — Pentatomidce, Coreidce , Berytidce , Lygceidce, Pyrrhocoridce , Tingi- dce, Capsidce.

6. Leaf Eating Insects.— All Phasmidce and Acridiidce, most Locustidce, some Gryllidce feed on leaves, as too do the larvae of Tenthre¬ dinidce, Melolontliid beetles, a few exceptional Carabids and Silphids, Epilachnids in both stages, Cantharid beetles, Chrysomelids in both stages, and Curculionids (rarely in the larval, almost always in the imaginal stage) have the same habit. The larvae of Lepidoptera in most cases are purely leaf eating.

7. Gall Insects. — In India, the known gall insects are typically Psyllids, Tineids, Chalcids (fig insects) and Cecidomyiids, the first pre¬ dominating. Other families recorded elsewhere are Tenthredinidce ( Nematus ), Cynipidce, Buprestidce ( Ethon ), Curculionidoe , Thysanoptera , Aphidce and Coccidce.

8. Tree-Boring Insects. — The following families make tunnels in trees ; Siricidce, Buprestidce , Cerambycidce, Curculionidce, Scolytidce, ( ? Brenthidse), Sesiidcef Cossidce , Hepialidce, Arbelidce.

9. Stem Borers. — A large number of borers live in green succulent stems as opposed to those living in hard woody tissues. The families concerned are, Gryllidce ( Cylindrodes ), Cephidce, Tenthredinidce , Phala- cridce, Erotylidce, Buprestidce , Mordellidce, Curculionidce , Scolytidce , (■ Castniidce ), Noctuidce , Pyralidce, Cecidomyiidce, Chloropidce, Agromyzidce, Geomyzidce , Ortalidce.

10. Boot Eating Insects. — Very little is known of the lives of underground insects, but the following groups contain species that feed on plant roots in the soil.

Melolonthid larvae.

Elaterid „

30

INTRODUCTION.

Curculionid larvae.

Pyralid „ (Crambidce, etc.).

Noctuid ,, (rarely).

Gryllid nymphs and adults.

Tipulid larvae.

A few of the Silphidw (Anisotomides) , Dascillidce and Bibionidce (Dilophus), have apparently the same habit.

11. Root Borers. — The Hepialids are conspicucus as root borers ; the Sagridce are said to have this habit as have some Eumolpids (Scelo- donta) and Galerucids ( Diabrotica , probably Aulacophora) ; some Pyralids have it, e.g., Schcenobiince ; exceptional Buprestidce ( Sphenoptera ) and Curculionidce (Cylas) are also known.

12 Root Sucking Insects. — Just as there are insects which suck plant tissues above ground, so others do below ground, but we know little of them. Probably a considerable number of species in the following families are concerned : Pentatomidce , Lygceidce, Cicadidce, Fulgoridce, Aphidce, Coccidce. In most cases it is probably the immature stages that have this habit. The best known example is the Phylloxera of the vine.

13. Internal Parasites of Vertebrates. — The Oestridce are the important group in which this habit is universal ; the Muscids that cause Myiasis may perhaps be included. We omit the many recorded cases of insects bred in the human alimentary canal as being exceptional.

14. External Parasites of Vertebrates. — So much is written of these we need only tabulate the families : Hemimeridce (on rats), Mal- lophaga, Platypsyllidce (on beavers), Hippoboscidce , Strehlidce, Nycteri- biidce, Aphaniptera, Polyctenidce, Cimicidce , Anoplura. We omit the non-parasitic biting flies.

15. Parasites of Insects. — The Parasitica among the Petiolate Hymenoptera, the Chrysididce, the parasitic Apidce , and the Tachinidce are the common parasitic insects. Other groups are the Mantispides (on spiders eggs), the Mordellids ( Emmenadia , etc.) (the Clerides), the Can- tharidce and Stylopidce. Of Diptera, little is known, but we may mention Nemestrinidce, Bombyliidce, Pipunculidce , Cyrtidce, Conopidce , Anihomyi- idce} Tachinidce, Sarcophagidce, Muscidce , Braulidce (external).

FOOD AND HABITAT.

31

16. Predators, Stinging. — A peculiar class are those insects which sting insects to paralyse them and lay them up for their young ; they include only Eumenidce, Pompilidce, Sphegidce , Scoliidce.

17. Predators, Biting and Sucking.— It is impossible to indicate with any accuracy the families containing predaceous insects ; probably a very large number of insects living in soil and under bark are predaceous,

notably beetles and smaller bugs, with remarks.

Forficulidce ; ?

Mantidce ; all.

Locustidcc ; some.

Gryllidce ; some, e.q., Schizodactylus. Odonata ; larvae and imagines. Raphidiides ; imagines.

Panorpides ; imagines. Myrmeleonides ; larvae all ; ima¬ gines ?

Ascalaphides ; ,, ,, ,,

Mantispides ; some.

II enter obiides ; larvae.

Chrysopides ; larvae ? imagines. Coniopterygides ; larvae.

Eumenidce ; the wasps eat insects. Vespidce ;

Cicindelidce ; all.

Carabidce ; practically all.

Silphidce ?

Staphylinidce ; probably all. Histeridce ; some, under bark. Trogositidce ; some.

Colydiidce ; some.

Cucujidce. „

Coccinellidce ; nearly all. Malacodermidce ; larvae all ; ima¬ gines ?

Cleridce ; all.

We tabulate a number of families

Anthribidce ; some.

Brenthidce ; imagines, larvae ? Lijcaenidce. ( Spalgis).

Noctuidce ; \ A few species feed Phycitince ; ) on Coccids.

T ineidce. ( Hypatim a) .

Some Culicid larvae. Blepharocerids ?

Therevids ; fly and larvae. Muscids ( Ochromyia) .

Some Anthomyiids & Ephydrids. Some Scatomyzids.

Leptidce ; larvae and flies. Tabanidce ; ,,

Asilidce ; all.

Empidce.

Dolichopidce.

Phoridce ; larvae.

Syrphidce ; ,,

Bombyliidce ?

Pentatomidce ; some.

Lygceidce ? many.

Aradidce ?

Henicocephalidce.

Reduviidce.

Phymatidce.

Saldidce,

32

INTRODUCTION.

18. Scavengers of Animal Matter. — There is a very large class of insects that live upon refuse animal or vegetable matter as apart from those feeding on live plant tissue or on the blood or tissues of animal life. Of this class, a portion feed in dung, corpses, etc. The family Scarabceidce are a notable example of the dung feeders, the Sarcophagidce notable as breeding in corpses, the Formicidce notable as carrying off dead insects. Other families are Blattidce, Silphidce , Staphylinidce , Hist- eridce, Nitidulidce ( ? ) Cleridce, Mycetophilidce , Bhyphidce, several Muscidce Acalyptratce (Borboridce, Sepsidce) and many Calyptratce, ( ? ) Phoridce.

19. Scavengers of Wood. — The insects that feed in dry or de¬ caying wood are a distinct class, but it is difficult in some cases to distin¬ guish them from the insects that prey on them. The following nine fami¬ lies are well known : Termitidce, Bostrichidce, Ptinidce ( Anobiides ), Lymexylonidce , Oedemeridce, Cerambycidce, Anthribidce , Scolytidce. Occa¬ sional Tenebrionids and Tineids may be added.

20. Scavengers of Vegetable Matter. — This is perhaps our largest individual class since we have not the data on which to break it up into such groups as in the case of Herbivores. It is of extreme im¬ portance in the daily routine of agricultural entomology to be able to distinguish the harmless insect eating dry dead leaves from the injurious one eating living parts of the plant. We can here only enumerate the more important families or those in which the habit is known, with the remark that fungi are included as food of this class as well as decay¬ ing leaves, fruits, blossoms and other soft parts of plants.

Aptera.

Blattidce.

Embiidce.

Psocidce (? feeding on living fungi). Passalidce (larvae).

Lucanidce (larvae).

Melolonthidce (larvae).

Scaphidiidce (fungi).

Histeridce ?

Nitidulidce.

Trogositidce (Peltides on fungi). Colydiidce.

Cryptophagidce.

Erotylidce (? fungi). Endomychidce (? fungi). Mycetceidce (fungi).

Latridiidce (fungi).

Byrrhidce (plant sap).

Cioidce (fungi).

Sphindidce (fungi).

Dascillidce ( Eucinetus on fungi). Elateridce (? larvae).

Nilionidce (fungi).

Melandryidce.

FOOD AND HABITAT.

33

Anthicidce.

Calandrince. Mycetophilidce (fungi). Chironomidce. Psychodidce.

Tipulidce.

Bibionidce .

Rhyphidce.

Lonchopteridce.

SyrphidcB.

Phoridce (larva?). Trypetidce. Sapromyzidce. Anthomyidce (larvse). Thysanoptera ?

A radidce (? fungi).

21. Household Insects. — We cannot separate this class of insect clearly from the last or from some others logically, because our household insects are simply originally free-living ones that have found a living in man’s dwellings. Nor can we make a separate division of them on the same scale as the Myrmecophilous insects, as we should perhaps logically do. The student will find further information under the heading Cosmopolitan insects below. The families concerned are : —

Thysanura. Blattidce. Gryllidce . Psocidce. Termitidce.

(N emopterides) Formicidce. SiVphidcB. Trogositidce.

Cucujidce.

Nitidulidce.

Ptinidce.

Bostrichidce .

Bruchidce.

Cerambycidce.

Pyralidce (Galleriince, Phycitince). Tineidce.

We have excluded external parasites of mammals, though they may rightly be included here, since they are classed as above.

II. Matitne Insects. — Very few insects live in, on, or within reach of salt water, probably on account of the difficulties of respiration due to the deposition of salts on evaporation of the water.

Anurida among Aptera , Mpophilus among Coleoptera , Campontia among Chironomidce , Eristalis and some allies among Syrphidce live in sea water, Halobata , a genus of Hydrometridce lives on the sea. Some Forficulidce , Carahidce, Cicindelidce , Staphylinidce , and Muscidce live in sea-weed on the beach.

III. Freshwater Insects. — The student will find fuller informa¬ tion under the heading Aquatic insects after the family Odonata below.

iil 3

34

INTRODUCTION.

W e give here simply a bald list of families, blit we make no attempt to class them into Herbivores, Parasites, Predators, and Scavengers as could well be done : —

Collembola.	(Pyralidce).
( Blattidce ).	Culicidce.
Ephemeridce.	Chironomidce.
Odonata.	Psychodidce.
Perlidce.	Dixidce.
Sialidce	Tipulidce.
(Hemerobiidce).	Blepharoceridce.
Trichoptera.	Simuliidce.
{Chalcidce).	Stratiomyidce.
Amphizoidce.	Tabanidce.
Pelobiidce.	{Syrphidce).
Haliplidce.	(. Acalyptrate Muscids).
Dytiscidce .	Hydrometridce.
Gyrinidce .	Pelogonidce.
Iiydrophilidce.	Nepidce.
Heteroceridce.	N aucoridce.
Parnidce.	Belostomidce.
Dascillidce.	Notonectidce.
Chrysomelidce.	Gorixidce.
( Curculionidce ). (. Eupterotidce ).	{Aphidce).

IV. Myrmecophilous. — The student will find fuller information regarding Myrmecophilous insects under Paussidce. The more import¬ ant families of which species are found in ant’s and termite’s nests are : —

Gryllidce . Melolonthidce. Paussidce . Silphidce. Gnostidce . Pselaphidce. Staphylinidce .

Histeridce.

Thorictidce.

Oossyphodidce.

Syrphidce.

Psyllidce.

Aphidce.

Coccidce,

INSECTS AND MAN.

35

Insects and Man. — With the exception of domestic animals there is no single group of animal life which enters more into the daily life of man than insects. They live on us and around us ; in our food, our clothes, our furniture, our houses ; we eat them or their products, we collect them and even sew them on our clothing. All people eat honey, use bees- wax, clothe themselves in silk, and there is no one who has not, at one time or another, been dependent upon some member of the insect world. The luxury of the present age of civilised peoples has brought into being industries connected solely with the collection of the more beautiful and striking forms, which are worked up into wall ornaments, paper weights, etc., and form a part of the art of this age. (Witness the advertisement in the Studio “ Artistic Cases of Tropical Butterflies, exquisite colours and designs, supplied to many Art Schools, etc.35) Man is, therefore, dependent on the insect world for so much, and though science may devise substitutes for the products derived from insects, some of them at least will never replace the genuine thing. No artificial honey will ever compare with the honey gathered by bees from thousands of flowers, fragrant of thyme or heather or logwood, though in this commercial age, chemically-prepared substitutes, composed of glucose and coal tar flavourings, are sold and accepted as genuine-; no substitute for bees- wax has been found, nor for shellac. It is likely that silk, as a commercial article among commercial nations, will be partly replaced by artificial substitutes, because the greatest value of true silk— durability— is of no value to an advanced civilisation which does not require to be clothed but costumed. Lac dye has been replaced by aniline, and though cochineal still holds its own for food colouring to some extent, it is probable that no insect- made dye will continue to hold its own against aniline dyes.

These are the useful insects ; there are many that affect man in other ways. Why is it that almost every dry form of food sold and dealt in by commerce must be placed in a sealed package ? Why are millions of tins used yearly in a single city ? Why do we pay at least a fourth again of the value of biscuits, simply because of the tin 1 Very largely because of the ubiquitous insect, who would get in and eat them, if these things were not thus protected. Let any house-keeper in India think for a moment of her store-room and the precautions she takes. Sugar must

36

INTRODUCTION.

be isolated or ants will carry it off ; flour must be in a tightly-closed tin, or moth, weevil or beetle gets in ; no sweet thing is safe, once opened, unless isolated on water, dried fruits of every kind are spoilt by beetles, grain is eaten by weevils ; pulse of all kinds harbours moths or beetles ; even tobacco and dried drugs are not exempt. Daily and hourly mankind is fighting the ravages of the insect world, which seeks to take from him his last ultimate asset, his stock of food. Think of the countless sealed mud grain-stores there are in India, many in every village, and all because of the insect life around us.

Let us take another aspect, that of disease ; malaria, enteric, typhoid, yellow fever, plague, filariasis and elephantiasis, sleeping sickness (? kala azar, black water fever), each and every one of these means a yearly total of deaths, premature and unnecessary, caused by the agency of insects. Think of the enormous total of deaths from plague in India, since plague came into India little more than a decade ago ; think of the desolation caused by sleeping sickness in Africa, of the countless cases of malaria in the tropics, of the extraordinary mortality from yellow fever, in old days, in the West Indies ; go to the West Indies and see the numerous cases of. elephantiasis ; men with legs like trees, men suffering from fever and ague for years which finally leaves them possessed of an elephant’s leg or arm ; think of the death-roll from enteric ! And after all this we may dimly realise the important part the insignificant insect world around us plays in our lives.

This may be equalled by that part played by insects in inducing disease among our domestic animals. This is a purely artificial case largely brought about both by our careless transfer of stock from one part of the world to another and by our own reckless disregard of the rudiments of science and of all reasonable precautions. Think again of the agriculturist and his foes ; of the locusts which lay waste a district, of the bollworm that takes a tenth of the cotton-crop in India, or perhaps three-quarters of it in an occasional year ; of the mothborer that kills one cane- shoot in three ; of the rice hi spa that causes famine or the rice grasshopper that destroys the paddy over a whole division : think of the trials of new and promising crops abandoned in the past, because insects ruined every plant on a small plot. Why does not tree cotton grow successfully in India, or improved American maize ; why has no fruit industry been established in places where fruit

INSECTS AND MAN.

37

grows ; why is shade-grown tobacco not a success, or the cultivation of sunflower or ground-nuts in North India ? What takes toll of every crop grown in this country to a greater or lesser extent ? Insects in every case insects ; and insects are a factor to be taken into account in agriculture all the world over.

Think of one3s daily life ! There are cockroaches that smell, fish insects that eat our papers, ants that carry off our sugar, “ gundies 53 and other smelly things that flavour our food when they fall in, wasps and hornets that sting, mosquitoes that bite and annoy, to say nothing of sand-flies, that no mosquito net keeps out, and the bug and flea which continually pester us, the mud wasps that build nests in our books and close our locks ; furniture beetles that wear out our chairs, the cheroot beetles that spoil our cigars, the book beetle that tunnels in our books, the moth that destroys our clothes. Daily and hourly we come in direct contact with insect life. Head the doleful comments of the Calcutta resident in August, asking why science cannot check the insects that come to his lamp during dinner and make his life a burden ; or the sad tale of the District Officer who had to vacate his bungalow because the wasps wanted it and had been accustomed to have it ; or again the tale of the telegraph stores which were hurriedly wanted in large quantities, but could not be touched because hornets had built- nests among them and actively resented any interference ; or that of the greatcoats ready to be distributed to the. army, each being found with neat little holes eaten out by beetles. Impartial judgment and a dispassionate consideration of facts will show that insects have fully exploited man, and, that though man may think that he is dominant, he really is not, and that not the least among his functions is that of providing food and occupation for insects.

It has been the custom of authors of all periods to refer all insects in some way to man’s well-being and economy. Every insect was, to them, created with some definite object from man's point of view ; and one has only to accompany a party of visitors round a collection, even in this twentieth century, to find this view still expressed. u What is the use of this ? 33 “Why was that created ? 33 Man may or may not be the central being of this earth, but to attempt to refer the activities of all insects in some way to his welfare is, at least, a problem that none

38

INTRODUCTION.

would attempt. An American author says : cc fleas are good for a dog, because they keep him from brooding over being a dog,” and explana¬ tions of this kind are possible where our domestic insects are concerned. But, were insects given to that kind of mentality and speculation (as they may be), it would be interesting to get their views on man and his place in their nature. Assuredly it would not agree with ours ; equally it may be, that, from any standpoint, whether material, mental, moral or spiritual, man is on no higher a level than insects ; and it might be better to classify our activities as they affected insects than to refer each insect to its “ use ” to us.

A rough classification of the ways in which insects affect man may be attempted, chiefly with a view to securing clearness of idea : —

1 . Cause damage to growing plants directly.

2. „ „ „ „ „ indirectly.

3. „ „ „ stored products.

4. ,, ,, ,, domestic animals directly.

5. „ ,, „ ,, „ indirectly.

6. Personally distasteful.

7. Transmit disease to man.

8. Assist agriculture directly.

9. ,, ,, indirectly.

10. Yield useful products.

It is needless to dilate upon the first class ; all the insects that feed upon, or live in growing plants that are useful to man, are included. Of the second, we would say that very little is known, but that there may be a very large class whose quite unimportant attacks on plants open the way to the entry of fungoid or bacterial diseases, which may then be¬ come of great importance. There is a great difference between the small damage caused by the cane- borer direct and that of the fungus it brings or lets in ; and the broader aspects of this question are as yet but little known. The insects injurious to stored products, to grain, flour, dry food-products of all kinds, to timber, furniture, books, paper, fabrics, to every kind of human merchandise, made of material of animal or vege table origin, these are only too painfully familiar to us all, and, in the genial warmth and moistness of the Indian climate, they find conditions admirably suited to their plentiful increase. Insects that directly injure

INSECTS AND MAN.

39

domestic animals include lice, ticks, fleas, horse-flies, bots, warbles and other parasites of cattle, horses, sheep, dogs, etc. Under the head of indirect injury is the transmission of disease, of which flies and pro¬ bably lice, fleas and horse-flies may be especially important.

Of those personally distasteful, it is hard to speak. The mosquito that bites and sings, the cockroach that flies around before rain, the eye- fly that thinks its proper sphere is man’s visual organ, the crawling cater¬ pillar that falls from, on high, each (and many more) is distasteful in some degree to different individuals. The dweller in Bengal is harried by hordes of perfectly amiable and delightful insects which join him when the lamps are lit. As I write, they swarm around me, in great variety, in pleasing profusion, adding, by their mere number and senseless gyrations, to the irritation caused by climate, weariness, liver, etc. In some places “ gundies ” ( Cydnince ) are pre-eminent, in other places green fly (Jassids) ; the geranium (Cydnus) is familiar to some, while our curse here is varied but largely composed of beetles (Scaritids chiefly). Whatever they are, their profusion, their ubiquitousness, their buzzings and their singed or oily corpses cause an annoyance only to be appreciated by experience, and which forms not the least of the ills we bear.

Elsewhere the reader will find an account of the insects transmitting human disease, the go-betweens, which add so enormously to the death- roll, which cripple so many lives and which constitute the first and greatest menace to human life in tropical countries.

So far all is ill and were we to consider this only, then insects would have but a sinister significance. There is another side and still taking our anthropocentric view, we may consider the classes of insects on which man’s welfare depends. A very large class of insects promote tillage, by burrowing and excavating in the soil ; they sweeten the soil and ren¬ der the growth of plants possible. This is especially the case in tropical India, where worms are not so abundant ; it is impossible to bring accurate proof of this, but it is easy to observe the countless borings of insects in undisturbed soil, especially under trees and where there has been no cultivation. In addition to this, insects do much directly to enrich the soil by carrying down dung, by burying carcasses, by causing the de¬ cay of fallen vegetable matter. It requires but little observation and thought to see how large a part insects play in this, and how greatly they

40

INTRODUCTION.

assist in keeping the earth sweet and wholesome, and in rapidly restoring to the soil available food ; with the bacteria, the fungi and similar organ¬ isms, they play a great part in the constant cycle of matter through the soil to some form of life and back to the soil again. In these ways insects assist agriculture directly. Another great function they exercise is in pollination ; a large proportion of plants are dependent upon insects for their fertilisation and we largely owe the beauty of many flower forms of the plant world to the need the plant has of attracting the insect and of inducing it to carry the pollen. The significance of insects in this respect requires no proof ; one can observe it both in the plants themselves and in their numerous insect visitors.

Indirectly insects are also a benefit as they check themselves and also help to keep down the undue prominence of weeds and particular forms of plant life. It is perhaps a paradox to ascribe as a virtue to insects the fact that they check themselves, because, if they did not exist, no check would be needed ; still it is a sober fact that parasitic insects are an important part of the insect world, and if they were absent for a few weeks, India would starve. Finally, there are the useful insects. These are connected with : — (a) silk, (b) lac, ( c ) wax, ( d ) dyes, (e) medicine, (/) food for man, ( g ) food for domestic animals, ( h ) ornament.

Those that yield silk are perhaps pre-eminent at present since im portant industries are dependent upon the silk excreted by the pupating caterpillar of one of four moths. The value of the exported silk in 1906-7 was 204 lakhs, but much more was produced and used in the country itself.

Lac is a large industry, one of the big staples of India, and, since its use is yearly growing and the source of supply is limited, it is an industry that brings increasing wealth to this country. The export in 1904-5 was valued at Us. 3,47,00,000 and, besides that, a large amount was used in India.

Wax is still an article of export, fetching a high price and we may see established in the future a large industry in the domesticated bee, for the production of both wax and honey. The yearly export for the last twenty years has fluctuated between 3,000 cwt. and 7,000 cwt. ; the value being between 2|- and 7 lakhs.

The importance of insects as dye producers is gone. Even lac is of no value except on a small scale. Medicine is still dependent upon insects

INSECTS AND MAN.

41

for Cantharidine, and these beetles may become a source of profit instead of a source of loss. As food, the bodies of insects are valuable to all but the most civilised nations ; while a not unimportant branch of trade is the collection of immature Formicidce (“ Ant’s Eggs ”) for feeding tame game birds and the capture of flies and other small insects as food for cage birds and the like is carried out on a large scale.

Finally, insects are enrolled, with every other description of natural product, in the list of materials used by woman in her personal adornment. This is not as insignificant as it may appear and, though few insects can be used directly (e.g.} Buprestids) many provide models for both art and millinery.

Fig. 1— Campodea staphylinus X [From Lubbock).

APTERA.

Wingless insects, the mouthparts mandibulate. Antennae and legs simple, the integument soft, clothed in scales or hairs, the segments undifferentiated and little co-adapted. There is no meta¬ morphosis, the development being gradual.

The order includes only a small number of minute wingless insects of extreme delicacy, supposed to be scavengers. The mouthparts are concealed, formed for biting. The legs are often long, and there are frequently abdominal appendages in the form of cerci, springs, etc. The body may be completely clothed with fine scales. There is no meta¬ morphosis and no changes take place in external appearance during life, except growth in size. Most of them live in concealment, their food con¬ sisting of dried or decaying vegetable matter, so far as is known. None are of importance economically, one genus, Lepisma, being a minor household pest.

Aptera are divided into two suborders and eight families. The Thysanura have ten abdominal segments and consist of four families. The Collembola have six abdominal segments with a peculiar tube-like structure below the first.

Campodeid^:.

The abdomen terminates in a pair of pointed cerci; the mouthparts are concealed .

The cosmopolitan insect Campodea staphylinus Westd. (Fig. 1) or a form very close to it occurs in India in damp moss, among damp decay¬ ing vegetation and in similar positions. It is a slender white insect, with moderately long antennae, with cylindrical body and with two anal cerci.

44

APTERA.

Fig. 2— Japyx sp. x 8.

Japygid,®.

The mouthparts are concealed. The body terminates in a pair of forceps.

These delicate insects will be readily mistaken for young Forficulidce, though the hidden mouthparts serve to distinguish them. They are said to live in moss and under leaves, stones, etc., on the soil, though nothing is on record as to their habits in India. Wood-Mason records finding a single species in Calcutta. (Journ. Asiat. Soc., Bengal, 1876 ; Ann. Nat. Hist. IV, 18). Japyx oudemannsi , Par., and J. indicus Oudem., are reported from Burmah. We have found one species (Fig. 2) common among decaying vegetation and in soil ; it is a delicate white in¬

sect, with the forceps chitinised and brown. It is common in Pusa and in Nagpur, and is probably common throughout the plains.

Machilid^e.

Well developed compound eyes are present.

The mouthparts are exserted and visible.

Apparently more than one species of this family occur in India, one on rocks and an¬ other among dry decaying leaves.

The latter is a dark grey insect found in the open. The body is elongate, a little over a quarter of an inch long (without the cerci) tapering from the base of the abdo¬ men to head and tail. Compound eyes are situated at the vertex of the head; the antennae are simple and tapering. The mouthparts are inconspicuous with long- maxillary and shorter labial palpi. The body is densely scaled and ends in three

Fig. 3— M A CHILIS POLYPOD A' X 4. {Brom Lubbock).

LEPISMIDAE.

45

cerci of which the middle is the longest. On the ventral surface of the second and third thoracic and each abdominal segment is a slender jointed appendage, those on the 6th, 7'th and 8th abdominal segments being longest. The legs are simple, tapering, the joints little differen¬ tiated, the tarsi two jointed. The female has a straight slender ovipositor. These little insects run on rocks and live in the cracks ; they are apparently nocturnal and appear to feed on lichens on the rocks.

Fig. 4-— Lepisma saccharina x 6. [From Lubbock),

Assmuthia is a termit- ophilous genus constituted by Escherich for the recep¬ tion of A. sfinosissima and A. inermis from India (Zool. Anz. 30, p. 744). Platy- stelea harbifer , Esch. is also recorded from nests of ter¬ mites in India.

LEPISMXDiE,

Body flattened , clothed in scales; eyes small , mouth - farts exserted.

The common fish insects of houses are members of this family and are found throughout India, as pract¬ ically throughout the world. Annandale has recorded Lefisma (Acrotelsa) collaris, Fabr.,asa fish insect of Cal¬ cutta (Journ. Asiat. Soc., Bengal, 1906, Vol. II, p. 346), and mentions this as the only recorded Indian species. The Himalayan species is apparently L . saccharina (Fig. 4).

46

APTERA.

Lepismids are common enough, though all may belong to the above species ; they shun light, live behind books among paper and in dark corners and are supposed to feed on starchy and sugary matter. Their body is clothed with flat scales which give them a greasy feel and the shiny appearance that characterises them. The surface of paper is commonly eaten by these insects probably because of the material used in glazing it and they can be in this way destructive.

Collemhola.

We are not aware of any described Indian species and only a few have been collected or observed. Species of the first two families appear to be common in damp situations as in decaying vegetable matter and wet moss, under stones by streams, where water drips and under bark. In general one finds such conditions for so brief a time in the plains that these delicate insects are probably not abundant, though they are so in the hills.

Collecting.—' Though of no economic importance, this order is well worth studying. The best method of collecting is to use a camel-hair brush, which is dipped into a mixture of glacial acetic acid and strong alcohol and with which the little insects can be caught and put in a tube of this mixture. They are afterwards transferred to 70% spirit. Berlese’s funnel trap is a good method of separating these insects from leaves, moss, etc.

PLATE I.

PLATE I

Fig. 1. Forficulid.

„ 2. Blattid

,, 3. Mantid.

,, 4. Phasmid.

,, 5. Acridiid.

„ 6. Locusbid.

„ 7. Gryliid.

. — Orthoptera.

.

U i , .}!< : ; H t y

’ :inin-Ah<^ I . -j

hLlUylH L ■

hlicihif y

■ bin i . !•

.biib i ? r> A ,C ! |

.fc&atfooj. .<) „

. .hnty'il) .V t<

ORTHOPTERA.

The antennae filiform or setaceous, of variable length. The mouthparts mandibulate, of the herbivorous type. The first pair of wings (tegmina) thickened, coloured or ornamented, narrow with nearly parallel sides. The second pair of wings large, membranous, with many fine nervures, hyaline and often coloured, folded below the first pair in repose. The forelegs formed for running or for capturing prey. The hind legs formed for running or leaping, in the latter case long and powerful Cerci are usually present. There is no perfect metamorphosis, the young differing from the adult chiefly in size, colour and the absence of functional wings and reproductive organs. A small proportion never become winged. The imaginal life is often longer than the nymphal life and occupies the greater part of active life. The order includes moderate to large sized insects, the majority scavengers or herbivores, a part predaceous on other insects. None are aquatic, social, or parasitic in living plants or insects.

The order is divided into seven clearly defined families, four of which form one series in which the hind legs are normal, three of which form a second series in which the hind legs are long and formed for leaping.

Forficulidce. Abdomen terminates in forceps. Teg¬ mina shortened. (Plate 1, fig. 1). Flattened, head deflexed, coxa? large. (Plate 1, fig. 2).

Forelegs raptorial. Prothorax long. (Plate 1, fig. 3).

Mesothorax long. (Plate 1, fig. 4).

Antennae short. Auditory organ on ab¬ domen. (Plate 1, fig. 5).

Antennae long. Auditory organ on fore¬ tibia. Tarsi four- jointed. (Plate l,fig. 6).

Antennae long.* Auditory organ on fore- tibia. Tarsi three- jointed. Teg¬ mina angled. (Plate 1, fig. 7).

Hind legs normal.

Hind legs

FORMED FOR LEAPING.

Blattidce.

Mantidce.

k. Phasmidce . Acridiidce.

Locustidce.

Gryllidce.

Except Tridactylince recognisable by the absence of hind tarsi and Gryllotalpa,

48

ORTHOPTERA.

Whilst these families are in the main clearly distinct, their relation¬ ships are by no means clear. Many entomologists regard the Forficuli- dce as a separate order (. Euplexoptera ). Blattidce are a geologically an¬ cient family whose connection with present day insects is not clear. PhasmidcB are also an ancient family from which may have branched the Mantidce on one side, the Acridiidce as well as the Locustidce and Gryllidce on the other. The last two are undoubtedly closely allied and such aberrant forms as Schizodactylus may well be placed in either.

Gryllidce is much more an aggregation of divergent tribes which may or may not have a common ancestor and so be included in one family, than is for instance Acridiidce which is a homogenous family. Until further evidence is available, a reasonable view is to regard Blattidce and Phasmidce as two archaic families still existing in a slightly modified form, from the latter of which descended the carnivorous Mantidce on one side, the common ancestor of the Acridiidce and the herbivorous Locustidce on the other, from which we have the carnivorous Locustidce , the burrowing crickets (from some such form as Schizodactylus ), the various other tribes of Gryllidce from other forms of primitive Locus¬ tidce. The Forficulidce are possibly an off-shoot from a primitive form of a Blattid ancestor and although retaining the characters of the primitive Orthopterous ancestor, are now distinct; it is equally probable that they are a distinct family more closely related to the primitive an¬ cestor of the Coleoptera. Whatever view may be held by science when more information is available, these seven families are usefully aggregat¬ ed in one order and the separate families are, as a rule, easy to distin¬ guish. It is unfortunate that the name Locusta should have been applied by Linnaeus to an insect that is not sufficiently close to the “locusts” to be in the same family ; the result is that taking the family name from the oldest named member, Locustidce does not include “locusts” which are Acridiidce. Entomologists sometimes evade the difficulty by naming the Locustid family Phasgonuridce or by transposing the names and ap¬ plying the name Locustidce to the Acridiidce. Mr. Kirby calls our Acridi- ids, Locustidce , our Locustids, Phasgonuridce , and our Gryllids, Achetidce.

The more important papers are the following : —

Stal, Recensio Orthopterorum (1873), Brunner, Revision du Sys- teme des Orthopteres (1893). Walker — Catalogue of Dermaptera Sal-

FORFIOULIDiE »

49

tatoria (1869-1871). Bolivar- — Orthopteres de St. Joseph's College (Ann. Soc. Ent. Fiance. 1897, p. 282 ; 1899, p. 761 ; 1901, p. 580).

FoRFicuLiDiE. — Earwigs .

Slender insects , the forewings short and covering the hindwings , which are large and radially folded ; the abdomen terminates in a fair of processes formed like forceps .

Fig. 5— An earwig with expanded wings.

The earwigs are medium-sized insects, rarely exceeding half an inch in length, rarely less than one quarter of an inch. The forceps at the extremity of the abdomen is characteristic of the family and while very diverse in form, is at once recognizable. There is a superficial resem¬ blance to the Staphylinid beetles but the latter never have forceps. The colours are sombre, black, brown and chestnut predominating; none are brightly coloured but all have the dull colour of insects that live in concealment or on the surface of the soil.

The head and body are somewhat flattened, the legs of moderate length, adapted to running swiftly on the surface of the soil. The an¬ tennas are about half the length • of the body, composed of a number of iil 4

50

ORTHOPTERA.

almost moniliform joints. The mouthparts are of the mandibulate type, the mandibles formed for crushing the food, the labium and maxillae for further mastication of the crushed food. The labial and maxillary pulps are apparently tactile organs, used to determine the nature of the food. The compound eyes are large with many facets; the thorax is of moderate size, its parts little coadapted ; the upper wings ( tegmina ) are short and thickened, rarely covering more than the base of the ab¬ domen. The lower wings fold into small compass, but are large, round, with short radial ribs, the outer part folding back on the basal, the basal folding radially as a fan does ; this wing is a beautiful structure, which can be opened with care and in which the method of closing is more com¬ plex than in the wings of any other insect. The abdomen is often broader than the rest of the body, the segments imbricate, terminating in the forceps which are in some species half the length of the whole body. These forceps vary immensely in size and structure in different species and are not constant in length even in the same sex of some species. Those of the male are commonly larger; bilateral symmetry is not always preserved, and in a few, one limb crosses the other. The sexes are similar in general appearance ; the male, however, having a greater number (nine) of visible ventral segments, the female having only seven. There are wingless forms, also some in which the tegmina are reduced to functionless lobes. These species resemble the young of winged species, but the latter have a softer integument, less developed forceps and a smaller number of joints in the antennae.

Little is known of the life history and habits of Indian earwigs, though that little agrees with what is known of the family elsewhere. Of these insects, as a whole, it may be said that the round white eggs are laid in a mass in the ground or in shelter, the female in some cases re¬ maining with them until they hatch. The young are white at first and while similar in general form to the adults are likely to be mistaken for Thysanura. The transformation is a gradual one, the number of moults not being known. The following account from Cuvier’s Natural History relates to Forficula auricularia , Linn, the European Earwig : —

“This curious insect,” observes Mr. Kirby, “so unjustly traduced by vulgar prejudice — as if the Creator had willed that the insect world should combine within itself examples of all that is most remarkable in

F0RFICULID2E.

51

every other department in nature — still more nearly approaches the habits of the hen in the care of her family — she absolutely sets upon her eggs, as if to hatch them — a fact which Frisch appears first to have no¬ ticed — and guards them with the greatest care. Degeer, having found an earwig thus occupied, removed her into a box where there was some earth, and scattered the eggs in all directions. She soon, however, col¬ lected them, one by one, with her jaws, into a heap, and assiduously sat upon them as before. The young ones which resemble the parent, ex¬ cept in wanting elytra and wings, and, strange to say, are, as soon as born, larger than the eggs which contained them, immediately upon being hatched, creep like a brood of chickens under the belly of the mo¬ ther who very quietly suffers them to push between her feet and will often, as Degeer found, sit over them in this posture for some hours. This remarkable fact I have myself witnessed, having found an earwig under a stone which accidentally turned over, setting upon a cluster of young ones, just as this celebrated naturalist has described.”

Diplatys longisetosa, Westw. has a remark¬ able nymph (fig. 6), in which the abdomen terminates in a pair of long many- join ted pro¬ cesses, of which the basal joint, at the final moult, is transformed into the forceps (Green, Trans. Ent. Soc., London, 1898, p. 381 [Dys- critina] ).

Equally little is recorded or known of the food of earwigs. Apparently it consists of decay¬ ing vegetable matter, of pollen, of the sap of plants and possibly often of small insects or other small forms of animal life. Earwigs are found in decaying trees, under bark, among rotting vege¬ tation and the deposit of leaves under trees, under stones, in flowers, in the tangled roots of plants (e.g., sugarcane), and in other similar situations; they hide away and live principally under shelter in damp places. Their form is adapted to running quickly and easily among leaves,

TOSA, NYMPH. [After Green).

grass, roots? etc., and flight is but rarely utilised.

52

ORTHOPTERA.

Lahidura lividipes and L. riparia, fly at night and come frequently to light, the only F orficulids observed to have this habit. They are not formed for actual burrowing, but are part of the Fauna of the surface of the ground, as are the Carabidce , Blattidce, Tenebrionidce , Lygceidce , etc. ; less is known of this “ surface fauna” than of any other, from the great difficulty of observation. The function of the forceps is a mystery that will be cleared up only when their food-habits and general life are better understood. It has been suggested that the forceps, though not actual weapons of defence, appear as such and give the insect a more formidable appearance which protects them against the enemies that occur in their habitat; a few species can actually use their forceps as feeble pinching organs and the power to do so may have been more fully developed in the more primitive species; there is also some reason to believe that the forceps are useful in carrying out the rather complex folding of the hind wing ; neither explanation is a satisfactory one.

Earwigs are most active in the rains and damp weather, being de¬ pendent upon moderately damp conditions ; in irrigated lands they are active throughout the year except when cold drives them to hibernation in shelter, as happens in colder parts of the plains. There appear to be no definite seasons for reproduction, and individuals of different ages may be found at any time. None are recorded as pests in India, though they are often believed to be injurious owing to their habit of coming to wounded tissues of plants to obtain sap ; they are thus found under very compromising conditions, but investigation has shown that the in¬ jury was caused by other insects, and there is no reason to believe that any can be regarded as pests. A few are constant frequenters of the sea-shore and are found almost throughout the world among the sea¬ weed and debris thrown up on the beach.

Earwigs are found throughout the temperate and tropical parts of the globe ; they are less common in India than in other countries, but a fair number of species are already known from India. They do not fall into well-marked sub-families and may be regarded as a distinct and fairly homogeneous family. Bormans and Krauss describe 76 species from India including Burmah, the majority being Burmese species. Kirby’s catalogue gives only 48 as Indian, and more have been described

FORFICULID.E.

53

from India by Burr; this does not include species found in Ceylon only. The number of known species will be increased when more attention is paid to this group in India, and some of the commonest species have been found to be undescribed. The student should consult Burr’s paper on Ceylon F orficulidse (Jour. Bombay Nat. Hist. Soc., XIV, 59), his papers on Indian species (Jour. Asiat. Soc. Bengal, 1905, p. 2/ , and 1906, p. 387) ; and his revision of part of the family (Trans. Ent. Soc., London, 1907, p. 91).

Diplatys is represented by several sub-tropical species ; D. longi - setosa , Wesfcw. is marked by the long multi- articulate setae of the nymph,

the basal joint of which is stated to be¬ come the forceps of the adult. Ford - pula has three species in India ; Labidura is represented by several species. L. riparia , Pall. L. bengalensis , Dohrn. (fig. 7), and L. lividipes Duf. are common in grass and are obtainable in numbers when a grass lawn is flooded with water. An- isolabis maritima, Gene, is a world-wide species, found in sea-weed on the beach. A. annulipes, Luc. is a wingless species, found abundantly in the plains on the soil. Labia minor , L., is a common insect not only in Asia but in Europe, Africa and America, found in flowers and on plants, rarely seen on the wing by day. Chelisoches is represented by nine species, Fig. 7— Labidura bengalensis. C. morio , Fabr. being spread over

the coasts of the South Pacific and Indian Oceans. C. melanocephalus , Dohrn. has been found commonly in sugarcane roots and also in the tunnels of the borer caterpillars in the cane. Apterygida gravidula, Gerst. is widespread and there are other species of this genus. Several species of Forficula are recorded, though the widespread F. auricularia , L., the common earwig of Europe, has not been found.

Collecting. — Earwigs will be found only by patient search if they are to be specially collected. In the course of general collecting one finds

54

O&TfrOPTERA.

them in flowers, under stones, among decaying vegetation and fallen leaves, among debris on the beach. Some are found in houses, especially in damp places, such as bathrooms in the hot weather ; others will be found at the roots of plants in the cold weather. Many come to sap, or are found in bored canes or in other situations where the sap of a plant is exposed. A few come to light, but this is rarely a useful me¬ thod of collecting them. When caught, they should be killed in a cyanide or B. C. bottle and pinned through the right wingcase. Care is needed to open the left lower wing, though this is not usually necessary.

WHERE INSECTS LIVE.

Insects are small creatures and very abundant; where are they all? At some times in the year one can easily gather at least one hundred thousand insects within one day over a space of, say a few acres; at another time there would not appear to be an insect obtainable in that space and yet the insects must be somewhere. It is when one comes to try to answer this question that one realizes the absolute truth of the statement that insects are to be found everywhere on the surface of the earth within a narrow zone which includes 20 feet of the solid soil, the vegetation that stretches up from the soil for some 100 feet, and to a slight extent the air above. Excepting for the moment the artificial erections of man, we are not far from the truth in saying that this zone is very completely occupied by insect life in some form or other. It may be hoped that light will be thrown on this point some day by the very careful investigation of the fauna of, say one square mile of the earth’s surface, including this zone we speak of, covering average areas of fallow, crop, grass land, bush, jungle and forest. The number of actual living insects in some form or other will be surprising. Commencing, say 20 feet down, there are the deeply burrowing insects, the termites, the dung beetles, the Cicadid nymphs, and the crickets ; within six feet of the sur¬ face we come to the insects that burrow, but do not go so deep ; the ants are conspicuous examples, as are all the above-mentioned insects which cannot go deep in some soils; Scarab aeid grubs are near the surface, as are Tipulid maggots, Cicindelid grubs ; nearer still to the surface are the surface crickets which only make tunnels as shelters, the many digger wasps and other boring Aculeates, the burrows of some Carabids, such as Anthia ; quite near the surface our fauna might be immense if we dug in winter, as we should find the countless pupae of the hibernating beetles, of moths, of Diptera ; we should also find the many adults which seek shelter there, as well as abundant egg masses and many half-grown larvae not yet ready to pupate. At any season there

WHERE INSECTS LIVE.

55

would be many such, not hibernating, but pupating or feeding or in the egg stage. The fauna of these few inches would be of great interest, and we venture to assert that, in India at least, much light would be thrown on many insects’ life-histories were it better known. Coming to the actual surface a large fauna would reward us where any fallen leaves and the like offered shelter and food ; we have referred often to this fauna, a very extensive medley of black and dark brown insects, such as Earwigs, Cockchafers, Embiids, Carabids, Staphylinids, Clavi- cornia of many families, Tenebrionid and other beetles, as well as the Cydnine division of the Pentatomidse, the Lygseidse, the Keduviids and the Capsids ; besides these there are the abundant larva) of beetles, of Diptera. a few of Lepidoptera, probably outnumbering all the remain¬ der and teeming in favourite places. A square foot of good soil covered in leaf mould offers a great variety anywhere, and it is only on very dry or hard soil that one can anywhere find a square foot unoccupied and usually no square inch. This little part of our zone is one centre, the home of the light-shunning surface fauna which works at night and which makes up so large and so unknown a portion of the fauna. It may be noted that this part of our fauna is probably far less important in sub¬ tropical India than it is in tropical India, the surface fauna in the former being comparatively small. Above that we are on surer ground and the variety is not so confusing ; for each part of our plants will have their own fauna ; the stems contain borers, the Buprestids, Cerambycids, Pyralids, Cossids and the like; the bark shelters multitudes if it is at all loose or decomposing and here again is a centre of activity, nor rivalling our chief centre but very important and crowded ; even the outside of our stems and trunks has cocoons and such like, as well as a whole fauna of its own in the case of a large tree round which debris collects. No one has ever described the fauna of the heap of de¬ caying leaves, bark, etc., found round the base of the trunk of a large pipal, for instance, which is the home of numberless insects, the resting place of pupse, the place of deposition of eggs. Our low plants have their own fauna, a very large one too, of herbivorous caterpillars, of leafmining Diptera, Coleoptera and Microlepidoptera, of gall insects, of the seed- eating species of caterpillars, of the sucking bugs and aphids ; apart from the plant, the two feet or so of air„space round the plants teems with the active flying forms, with bees and wasps, with butterflies and beetles, with flies and grasshoppers, all the lives that lives on and round and among low plants. It is this fauna which is, in moist sub-tropical India, with its immense flora, so extensive and which is of much greater relative im¬ portance in this zone than it is in tropical India. A reduplication of this fauna is found higher up, in or among the taller forms of vegetation, such as bamboos and grasses and to a large extent this fauna is quite dis¬ tinct if, as is true, human beings live wholly in the six feet of air space lying immediately over the soil, so also insects are largely restricted each to its particular zone, and we believe there is a very distinct and peculiar fauna of the air at the tree levels ; the dancing insects that may be seen

ORTHOPTERA.

56

in such myriads on a clear still day are certainly peculiar, and it is at least probable that a number never come, in this form, within our ken, but remain at higher levels ; then too no one knows what insects are found in the air above the trees or how far this zone extends ; what do swallows get when they are hawking high up, far above the trees ? Ait- ken speaks of a butterfly (M elanitis ismene) soaring far above into the air and no one knows what countless forms of winged insects may not go to these levels as soon as they emerge. There must be a limit to this zone, but we would hesitate where to put it unless, for the plains, we give an outside limit of, say 3,000 feet. When the day of flying machines- dawns we shall certainly find insects of interesting kinds above the trees, and we should like to see ‘ 4 kite ’ ’ nets employed to investigate the fauna.

It is perhaps not unprofitable to consider, in the light of the above remarks, how little of our insect world we probably know or attempt to know. In this country, progress beyond the stage of classifying and naming the insects most easily got has scarcely been made at all and this must come first ; but it is certain that the only insects that have been found, named and placed in Museums are those which fly by day, or which live on bushes, etc., above ground, or which come to light. A great number of insects come to light, notably perhaps a part of the ‘ 'surface soil fauna” and other retiring insects; but we do not know that there are not hordes which never come to light, which are never seen, and of which we are quite ignorant. This is true probably of all countries and the fauna of the soil, except as regards the large forms, is extremely little known even where naturalists andj collectors abound. (The same is to some extent true of freshwater.) How much more will this not be the case with the tropics, especially with the drier parts where much of the fauna is known to go to the soil. We know from experiment that many species go to the surface soil to spend the hot weather ; but there are no records that they were ever found there ; put out a light trap on a still moist evening during the monsoon and see the countless insects that come and the number of kinds ; very many are never found in any other way, yet they and how many more, must be hidden somewhere.

Blattid^e. — Cockroaches,

Flattened insects, the large forewings lying flat on the abdomen, completely covering the hindwings. Coxce large and covering the lower surface of the thorax. The head turned down and hidden from above.

Cockroaches have a very characteristic general appearance and are usually recognizable at sight ; they include small fragile insects of a

BLATTIDiE.

57

quarter of an inch in length to larger robust forms which measure nearly two inches. They are coloured in sombre sheds of brown and black, only a few species with conspicuous bands or spots of yellow or orange which may constitute a degree of warning coloration and are usually found in the diurnal species living to some extent exposed. The an¬ tennae are long and filiform, functioning as delicate sense organs ; the mouth-parts are of the non-predaceous biting type, the mandibles short and massive, the labial and maxillary palpi well developed. The body is generally soft, the chitinous plates of the integument not firmly united and the chitin usually less thick than in other insects. The flattened

body and slippery surface enable the insect to hide in crevices and render it more difficult to capture. The abdomen terminates in a pair of short jointed cerci, whose precise func¬ tion is not known. The legs are long, thickly spined and formed for quick running ; the first pair are reduced in some species. (Fig. 8.) Males and females are generally similar in appearance, the former in some instances with a pair of slender stvles at the genital open-

Fig. 8 — POLYPHAGA jEGYPTIACA. .

From below. ing. In several species the

wings and tegnima are absent or only imperfectly developed, this being correlated with the general disuse of the wings throughout the family. It is difficult to distinguish the wingless adult from a nymph of a winged form ; the presence of lobes at the hind angles of the mesonotum and metanotum shows the insect to be a nymph of a winged species, in most cases.

The life-history of all known species agrees in the general features.

"58

ORTHOPTERA.

Eggs are laid in the forms of a capsule, (fig. 9) a brown hard structure of characteristic form containing a considerable number of eggs. In Periplaneta americana, out of seven egg- capsules, four contained 16 eggs, two contained 18 and one only 12. Each capsule consists of a

Fig. 9.— Styloygia rhqmbifolia.

Adult female and egg-case.

double row of cigar-shaped eggs, surrounded by a chitinous coating which is joined by a wavy line which runs along the one end of the rows of eggs ; when the eggs hatch, this line opens, allowing the young emerge. It is probable that the expansion of the eggs before hatching, a common phenomenon, is the cause of the opening of the egg-capsule, but it is also stated that the cement joining the edges is softened by a fluid secreted by the embryo just before hatching. The egg-capsule is not always deposited by the female as soon as formed, but is in some species carried in the oviduct almost until hatching ; in a few foreign species this habit is carried to the extreme, and the eggs are carried till the young hatch. An egg cluster of Periplaneta americana laid on the 2nd July, hatched on 27th July and the nymphs were only half-grown at

blattid^.

59

the end of the following April. The young which emerge from the egg- capsule are in general form similar to the adult, the skin softer, the antennae and cerci with fewer joints, the wings absent. The number of moults is not known ; in captivity, development is slow, the common household species ( Periplaneta americana ), requiring several months to come to maturity. There is reason to believe this is the case also with the free-living species, and since the possession of wings is usually a matter of slight importance and the habits remain unchanged, there would not appear to be any necessity for quick iiymphal development. The total length of the life history is not known, but the imaginal, like the nymphal, life is probably comparatively long.

In all stages, cockroaches are found amongst fallen leaves, on the surface of the soil, under stones, in thick grass, and on trees and plants. The majority are nocturnal, living in concealment on the surface of the soil and forming a part of the large ‘‘surface fauna.” The tree and bush species are diurnal in habit. A few are household insects living in buildings and these are undoubtedly wild free-living species which have migrated into man’s dwellings. The food consists of dead animal and vegetable matter; these insects are “scavengers” and none is known to feed on living plant tissue or to attack living insects. Plant sap, de¬ caying plant tissue, dead insects and the like probably represents the food of the free-living species. The household species have the same food-habits, a great variety of animal and vegetable substances forming their food while their dead brethren are freely eaten when hunger presses. Nothing is known as to the activities of Indian species during the different seasons. Hibernation, where necessary, is apparently pass¬ ed in any stage and there appear to be no special ‘ ‘seasons’ ’ when cockroaches breed. Excessive cold, excessive heat, drought or hunger cause a cessation of reproduction, development and activity but no definite seasons have been made out. No species is known as a pest, though those which live in houses are objectionable and destructive.

Since these insects are dependent upon crumbs, scraps, and access to human food, cleanliness and care should prevent them thriving. Where they are abundant, the simplest precaution is the use of borax, mixed with double its weight of syrup, as a poison ; many ingenious traps are also useful when baited with intoxicating liquor. The principal check

60

ORTHOPTERA.

on cockroaches are egg-parasites ; the ichneumons of the genus Evania lay their eggs in the egg capsules of cockroaches and the household species are not exempt from attack. Field cockroaches are attacked by fossorial wasps of the genus Ampulex, which sting them, deposit them in holes or crevices and lay an egg on them. The unpleasant odour of the household cockroaches is probably protective and is due to the se¬ cretion of liquid from glands placed between the 5th and 6th abdominal segments. (Minchin, Q. J. M. S., XXIX.)

It is known that cockroaches contain internal parasites belonging to the Gregarine division of the Protozoa, as well as parasitic bacteria, Nematodes ( Oxyuris ), Hair worms ( Gordius ) and a Filaria. It is also probable that the large centipedes which enter houses in India are

seeking blattids. Rats also feed on cockroaches.

The family is a comparatively large one, with many described species, occurring in all parts of the globe. The majority of the Indian species are described by Brunner and Bolivar.

Kirby’ s recent catalogue of the fami¬ ly lists 123 Indian species, which probably include the majority of the larger forms. The family is being listed by R. Shelf ord in Genera In- sectorum ; it is divided into eleven tribes by Brunner, but it is unneces¬ sary to consider these in this place.

Phyllodromia (Blatta) germanica, Linn.

Fig. 10— Phyllodromia humber- „ n

ti an a. x 2§. is one of the common small species

found in houses in India and now cosmopolitan, probably introduced to India from Europe. P. humbertiana , Sauss. (cognata) (fig. 10) is a small brown species, the prothorax marked with black and light brown. It is perhaps the most common field species, found among decaying vegetation and also on trees ; its eggs are laid on the leaves and bark of trees. On the soil is its wingless nymph, a small black insect with me¬ dian and lateral light stripes. Phyllodromia suppellectilium , Serv., is

BLATTIDiE.

61

the small household species, common throughout the tropics ; it is winged, of a brown colour with varied dark markings.

Stylopyga (Blatta) orientaiis, Linn, is a widespread species, believed to have been introduced to Europe from tropical Asia and now carried

over the world in ships. It is a dark coloured insect of a length of a little over an inch ; the tegmina do not reach to the apex of the abdomen and cover only the basal five

segments. The males alone are winged. The development in Europe is stated to occupy as much as four years, the duration of each instar being very long. Stylopyga rhombifolia, Stoll, (fig. 9) is a larger Fig. 11— Periplaneta Australasia:. wjngiess form, brown, with varied

yellow markings, found also in houses. This is the most common household species next to the large winged Periplaneta australasice , F. Periplaneta includes the two large cockroaches so common in houses and on board ships. Both are winged, red brown with lighter markings on the pro thorax. P. australasice , Fabr. (fig. 11) is smaller than P‘ americana , Linn, the prothorax more wholly dark. The latter has the startling habit of flying about in the house before rain falls and is accounted a reliable weather prophet. This habit is possibly a relic of the instinct of its original free-living ancestor, which flew up into safety before the fall of heavy rain. Rhyparobia maderce, Fabr. is a cosmopolitan species, carried over the world by commerce. Leucophcea surinamensis , Linn, is a smaller thickset insect, the prothorax black, the tegmina brown ; it is common in the open and is widespread over the tropics. Panesthia regalis , Wlk. is a peculiarly striking species, black with a broad band of orange across the tegmina. It is one of the rarer plains’ species. Corydia petiveriana , Linn, is a beautiful cockroach of South India, the tegmina having large white spots. Hete- rogamia (Polyphaga) indica, Wlk. resembles a large round woodlouse, wingless and nearly circular in outline.

Collecting. — Cockroaches are found by searching under stones, among fallen leaves, on herbage and bushes, on the bark of trees, and

62

ORTHOPTERA.

among the debris that accumulates at the foot of the trunk of a large tree. The smaller ones are found also in thick (doab) grass in the hot weather. Syrup or fruit juice smeared on the bark of trees is a good bait but unless this is alcoholised, it must be examined soon after dark ; if strongly alcoholised the insects get drunk and may be found at any time in the night till dawn. A few species are attracted by light. When caught and killed, they should be pinned through the right tegmen near the base, the legs and antennae set. Rearing is slow and difficult ; the right conditions of moisture and food must be given with plenty of shelter and space.

COSMOPOLITAN INSECTS.

A considerable number of insects have been carried by man from one country to another and have succeeded in establishing themselves not in one country only but in a large number of countries ; the spread of these insects is continuing and they will in time be world wide. These species are to a large extent those which can live in houses, or which infest grain and other merchandise, or which have been carried on living animals and plants. Naturally the household and grain insects predominate, since commerce is carried on between large cities in which these insects thrive, whereas those infesting plants have not the same chance of surviving in all cases. Many of our common house¬ hold insects are cosmopolitan ; the common silver fish of houses is now widespread and will become more so ; the Cockroaches, Stylopyga orientalis , Periplaneta americana and P. australasice, Rhyparobia maderce and Leucophcea surinamensis, are common in India as else¬ where ; with them have gone their parasite Evania appendigaster , now a common insect and met with on board ship. It is probable that our household Psocids are also the same as the European though we are not aware that this has yet been substantiated. Ants, ( e.g ., Monomo- rium) as is well known, constantly come with shipments of goods and establish themselves successfully in new cities.

A host of beetles are cosmopolites. Hamilton gives a list of 100 beetles which he styles cosmopolite or nearly so ; this refers more especially to Europe and North America and indicates how large a number of insects have been carried by commerce and have succeeded in establishing themselves in new countries. Only a small number of these appear to originate in the East.

The following are Cosmopolitan beetles apparently found in India, gome possibly originating there (indicated by*).

COSMOPOLITAN INSECTS.

63

Silvanus surinamensis . Lcemophlceus ferrugineus.

„ pusillus. Dermestes vulpinus. Carpophilus hemipterus. Trogosita mauritanica. Necrobia rufipes.

Necrobia ruficollis. Necrobia violacea. Gibbium scotias.

* Sitodrepa panicea. Dinoderus pusillus. Bruchus chinensis.

,, emarginatus.

* Tenebrio molitor Linn.

* Tribolium ferrugineum.

* ,, confusum.

* Calandra oryzce.

* „ granaria. Arcecerus fasciculatus.

Among Lepidoptera some of the genus Ephestia are constantly car¬ ried and are now almost universal ; so also are such forms as Tinea pellionella, Setomorpha rutella, and other clothes moths. Of the flies, we know of few ; Eristalis tenax is widespread and the common house¬ flies such as Musca domestica are world wide, as are some of the fleas ; the cheese maggot, Piophila casei is also carried in its food and establishes itself successfully.

Finally the malodorous bug Cimex lectularius is sufficiently familiar. The above are all household or grain pests and would naturally be readily spread. Amongst animal pests it is sufficient to mention the fly Stomoxys calcitrans established throughout India, as well as the three bot flies of the horse, cow and sheep, (ticks also are carried). When we turn to plant parasites, there are fewer true cosmopolites since the vegetation varies so much, and since climatic conditions affect the insects more. (See Agric. Journ., India, III, No. 3. “ Introduced

Insect Pests.” ) Many scale insects are extremely widespread and nume¬ rous species are known to have been carried, some reaching India. In fact, the introduction of living plants is practically certain to mean the introduction of scale insects if precautions are not taken. We can enumerate 25 species probably introduced to or from India, and we have seen more than one on consignment of plants from abroad. How our Aphids reached India is not clear but our worst are all cosmo¬ polites and have probably come on plants. Of other insects, it is ex¬ tremely hard to speak; a few are cosmopolitan, such as Chloridea obsoleta , Danais plexippus , Vanessa cardui, Hellula undalis, Nomophila noctuella, Plutella maculipennis , but there is no evidence that they are spread by man and this cosmopolitanism possibly antedates man. Phthorimcea operculella is a widespread insect introduced to India probably in recent years and is the sole instance of its class we know of.

We have barely touched the fringe of this subject as alone is possible in this place. Enough has been said to show that insects are carried by man and though India has not suffered from this cause, as for instance, America and the West Indies have, yet when more is known it may be found that India has got nearly as much as she has given,

64

ORTHOPTERA.

Mantid^e. — Preying Mantises.

The forelegs raptorial, long, the femora and tibice spiny.

The head deflexed. The prothorax elongate.

A moderately large family, recognizable by the raptorial forelegs, in which the tibia works in opposition to the femur like the blades of a

Fig. P2— Hierodula coarctata.

And left cercus.

scissors and both are wholly or partially spined. Where this character is insuffic separate from Phasmidce, the length of the prothorax is

sufficier-t, rms oeing short in the latter family. Mantises are commonly of large size and include no insects of less length than half an inch while some attain to four and even six inches. In appearance, these insects are extremely striking, including some of the most picturesque and bizarre forms of insect life. The form and colour is cryptic, designed to produce a resemblance to natural objects in their surroundings which is extremely marked. Many are stick-like, elongate, coloured in tones of brown and black as is a dry twig ; in these, the attitude assists the decept: , the creature poising itself on its posterior legs and swaying

MANTIDjE.

65

lightly from side to side as if moved by the breeze. Others that live in grass are slender and grass coloured, either “dry grass colour, 5 ’ green or green with the antennae and cerci coloured like the dry tips of withered grass. Others are leaf green, living among the leaves of bushes or are the colour of bark and are found on tree trunks. The most striking instance is the Orchid mantis, Gongylus gongyloides, which is a floral simu¬ lator, the body and wings so formed as to suggest a flower when a par¬ ticular attitude is assumed. In this attitude, the lower surface suggests a blue flower, and insects coming to it are destroyed by the forelegs. Williams (Trans. Ent. Soc. Lond., 1904, p. 125) states that the upper surface can be so arranged as to simulate an orchid flower, this being primarily as a means of defence (cryptic), the blue flower resemblance alone being used to obtain food. In general the cryptic form and colour serves the double object of protecting the insect from foes and allowing it to be invisible to other insects which it captures when they come within reach.

The antennae are filiform, in some short and inconspicuous, in others long. The head is elongate, sometimes produced at the apex, the compound eyes are large, the head very mobile and the insect has a curious habit of turning the head to look intelligently . en at a human being as if it really saw it. The mouthparts are similar to those of the rest of the order, short biting mouthparts, the mandibles not elongate as in other predaceous insects, since the prey is captured by the forelegs and the jaws are solely for mastication. The prothorax is long, sometimes nearly half the length of the body, and this is ap¬ parently an adaptation to secure great mobility for the forelegs and head. The forewings are of moderate size, thickened, colo1 red and covering the large folded hindwings, which are hyaline often coloured. Wingless species occur but rarely, one or both seL^r ^ without either tegmina or wings. Wood-Mason describes stridulatory structures in certain Mantidce , but there appears to be no direct evidence that sounds are actually produced (Trans. Ent. Soc. London, 1878, p. 263). The abdomen is often expanded in a leaf-like manner and is carried in striking attitudes to aid the cryptic resemblance. The abdo¬ men terminates in a pair of short cerci. The forelegs are beautifully formed, the tibia closing on to the femur ; as both are set with ;:nes, an insect caught in them is firmly held and can be brought up to mouth

TO 5

66

ORTHOPTERA.

to be eaten. The tibia is sometimes as long as the femur, sometimes very short and only closing on the apex of the femur, this portion of the femur alone being spined, the remainder smooth. Wood-Mason des¬ cribes femoral brushes used to keep the eyes and ocelli clean and found, he says, in the nymphs just hatched and in all later stages (Proc. Asiat. Soc. Bengal, 1876, p. 123). The posterior legs are long and enable the insect to run actively, as well as to balance itself ready to turn or to dart forward. There are few more striking insects than a mantis in its natural habitat on a plant waiting for food ; balanced on the two pairs of legs, it looks from side to side, turning the head with quick motions and seeming to look intently from the large eyes ; the antennae are active, moving constantly, the forelegs drawn up under the head but ready to dart out ; the creature is so intent, the attitude so expectant and yet suggestive of cunning ; in an instant it stiffens, becomes rigid, every part still, the long forelegs extended; should its prey alight near, it moves stealthily, stalking it as a cat does a bird, gradually drawing near

Fig. 13 -Mantid egg-mass and newly emerged! nymph,

THE LATTER MUCH ENLARGED.

MANTIDiE.

67

till its forelegs strike and the insect is held securely, drawn up to the mouth and devoured.

Fig. 14— Deiphobe ocellata.

The female deposits her eggs in a charac¬ teristic large egg case, (fig. 13) fixed to a plant. The egg case is made of gummy matter secreted by the female, which comes out as a frothy mass, and sets hard in a short time ; taking a firm position on the plant, with head down and the tip of the abdomen touching the plant, she extrudes a mass of frothy gum and with the end of the abdomen works it into the shape characteristic ; as soon as the base is formed and some amount of gum used, eggs are deposited in the midst of the gum. The emission of eggs and gum continues, the eggs in the middle, the gum round, until the whole egg mass is built up, layer by layer, when she finishes it off with gum and the whole hardens to a watertight obj ect firm-

68

ORTHOPTERA.

ly secured to the plant. The eggs are in regular rows inside the egg case and the whole mass will last through the winter on the plant. The young mantids emerge from the egg almost simultaneously and are small active insects often dark coloured and with a general resemblance to an ant (fig. 13). Shelford records the mimicry of the nymph of Hymenopus bicornus for the nymph of a Keduviid bug, Eulyes amoena (Proc. Zool. Soc. London, 1902, p. 230). They are active and lead an active life until they are full grown. In general their habits are not those of the parents, the young seeking small insects on plants or on the soil, and only adopting the peculiar habits of their parents as they pro¬ gress towards maturity. The form and attitude of the young is fre¬ quently very striking, though different to that of the adult, and there is a large field for investigation into the habits and resemblances of these nymphs. All are predaceous at all times of their life ; the food of the full grown insect is large living insects, which are caught when they come within reach of the waiting mantis. None are vegetarian, none are injurious, but the group comes into the class we may denominate as 4 ‘General Predators, 5 ’ feeding on such insects as come to them and not being specially adapted to special insects. The length of the life history is not known. Hibernation appears to take place chiefly in the egg stage ; eggmasses are laid in early November in the plains, and hatch in early March. This is not the only time that eggs are laid, as they may be found during the rains. Wood-Mason found eggs laid by Mantis sp. to hatch in 18 days (July 17th to August 4th), while those of Schizocephala bicornis took 30 days (July 17th to August 16th). Nymphs and adults of bark-infesting species have been found in winter under the bark of trees, and this appears to be the normal hibernation of such as can find shelter. Throughout the remaining months these insects are active and there appear to be no special periods when they breed or multiply extensively. They are distributed throughout India, more abundantly in the jungle but still commonly in the cultivated plains. They are essentially tropical insects, and are rare or non-existent in temperate climates. The eggmasses are the habitat of parasitic Chalcidce , the females of which have long ovipositors with which they pierce the eggmass and reach the eggs within. Apparently a large proportion of the eggmasses are parasitised. Other enemies are not known.

MANT1D A?.

69

Mcmtidce are far less numerous than some other groups of Orthoptera and fewer species occur.

Wood-Mason catalogued the Mcmtidce and more recently Mr. Kirby’s catalogue has been issued by the British Museum (Cat. of Orth., pt. I). In this 82 species are listed as Indian divided as follows -

Amorphoscelinae 1, Hemiaphilinae 7, Chaeradodinae 1, Mantinse 43, Miopteryginae 0, Creobotinae 17, Vatinae 10, Empusiinae 3.

The majority of Indian Mantidae belong to genera widespread over the Indo-Malayan region. Five genera are purely Indian, accepting India in the broad sense, these being Sphendctle, Phyllothelys, Heterochae- tula, Aethalochroa and Gongylus. Empusa is widespread, having but one Indian species, but occurring also in Africa, South Europe and Western Asia.

Creoboter urbana, Fabr. is a common small green form, each tegmen with a yellow black -ringed eye-spot ; it is an active species found upon bushes. Hierodula Westwoodi, Sss. and H. coarctata, Westw. (fig. 12) are the robuster green insect seen upon bushes and in crops, which are the most familiar 4 ‘Mantis’ ’ in India. The former has been seen eating Scutellera nobilis. Eremoplana microptera, Wlk. is a long slender species of a dull brown colour with a narrow green costal stripe, found upon low bushes in the plains. It comes freely to light. Hvlmbertiella indica, Sss. is a smaller dull grey species found upon the bark of trees, where its colouring renders it very inconspicuous. Schizocephalus bicornis, L. is one of the most delightful of the insects one can find commonly in the plains. It is a very long, attenuated insect, with long slender legs, and with short wings folding tightly round the body. Its colouring is green and the antennae and anal cerci are both the colour of a dry grass blade. Sitting among the grass, the insect is indistinguishable from the grass blades round it ; its antennae or anal cerci give the idea of grass just dry¬ ing at the tip and one may search for these insects and not find one when they are abundant under one’s eyes at the time. They are slow in move¬ ment and the femur is armed only at the tip, the tibia very short. ~ < ,

Two species of Gongylus occur in India, of which we figure one. G. gongyloides, Linn. (fig. 15) is a notorious insect of which much has been written. G. trachelophyllus, Burm. is the commoner Indian

70

ORTHOPTERA.

insect, a graceful creature coloured in tints of yellow and brown and commonly found in jungles and woods.

Fig. 15— Gongylus gongyloides.

Collecting. — The great number of mantids are found upon bushes, in grass, on the bark of trees. They are most abundant upon bushes, rare upon small crops. A number will be found in the bag when it is used to sweep insects on grass. These insects should never be included with others in a box or bottle while alive, but should be confined sepa¬ rately or at once killed. They are best pinned through the right wing case or prothorax, the left wings being set. Bearing is exceedingly difficult in most cases, though the eggs hatch readily, as the special food of the young cannot be ascertained or easily procured. What is now specially required is careful observation of the food of these insects ; we are not aware of any definite observations on the food of individual Indian species and no proper estimate of their economic value can be made until we have such facts.

PHASMIDjE.

71

Phasmid^. — Stick and leaf insects.

The prothorax small , mesothorax large. Tegmina smaU or absent ; wings often absent. Cerci of one joint only.

Fig. 16— Necroscia pholidotus, westw , male9

72

ORTHOPTERA.

A smaller group of insects, distinct from Mantidce by the small prothorax and by the forelegs which are not formed for the capture of prey ; they are distinct from the jumping Orthoptera by the hind legs, which are not formed for leaping. None of these insects are small, whilst some are of great length, four to six inches being the usual size for the full grown ones. They present a great variety of form and colour, some being stick-like, others leaf-like or resembling a blade of grass, while others closely resemble other natural objects. The colour schemes bear out this cryptic form and their whole appearance is designed to give them so close a resemblance to their habitat that they will escape the observation of their foes.

The antennae are commonly many jointed and long. The head is small, and not deflexed. The mesothorax is long, as is usually the meta¬ thorax in the elongated species. The legs are long, formed for walking and without special structures. The tegmina are small or wholly absent, even in forms which have large hindwings. In many species the wings are wholly absent either in both sexes, or in the female only. The male has claspers at the end of the abdomen, the female a ventral process which

directs the eggs as they are extruded. The differences be¬ tween the sexes are often very great, the male small, active and winged ; the female large, clumsy and unwinged.

The eggs are laid singly, dropped like seeds upon the ground. They are often of peculiar form, with very thick covering, and closely resembl¬ ing hard seeds. Little is known of the life history of Indian species. The young are similar to the adult and are stated to develop slowly. There is a line of weakness (suture) between Fig. 17-Phyllium scythe, nymph. the trochanter and femur,

PHASMIDJE.

73

which enables the insect to throw off a leg with ease, this leg being later formed anew. It has been observed that not only is this useful as a pro¬ tection from enemies but also in moulting, as few Phasmids can moult successfully without remaining attached to the cast skin by a leg, and this adaptation enables the moult to be completed, though with the loss of a limb. (Bordage.) The food is apparently wholly vegetable and no cases are recorded of these insects being carnivorous ; they eat the leaves of plants and some possibly feed upon lichens. None are injurious in India and their habitat is practically confined to the forest and jungle areas of the warmer parts of India. Not much is known of

Fig. 18— Phyllium scythe.

74

ORTHOPTERA.

Indian species and none are likely to be found in the cultivated areas. Westwood figures a number of Indian species (Cab. Or. Entom., 1847). Brunner listed 19 from Burma, and Bolivar 26 from South India. Kir¬ by’s Catalogue enumerates 65 Indian species.

Pulchriphyllium (Phyllium) scythe Or. (figs. 17, 18) is a large leaf¬ like insect, whose life history is described by Murray and quoted in Sharp’s Insects. It occurs in forest areas in Assam.

AcRimiDiE. — Short-horned Grasshoppers.

The antennce short ; the auditory organ on the first abdominal segment; the ovipositor composed of short valves formed for digging ; tarsi three-jointed. Hind legs long , and saltatorial.

Fig. 19— Acridium m el a nocorn e.

A family which can scarcely ever be confused in the field ; the short antennse and leaping hind legs mark a true grasshopper at once. The size varies from a length of a quarter and a wing span of nearly half an inch to a length of over two inches and a wing span of three to four. The majority are less than one inch long, the smallest among the Tetri- ginee, the largest among the Acridiinoe. Size is usually sufficiently constant to be valuable as an indication of species. With few exceptions the colour is cryptic ; the colour schemes harmonize so closely with the natural surroundings that the insects are difficult to see. Since the life is a long one and the surroundings vary with the change of season, it is common to find that, while the nymph is also cryptically coloured, the colour may not be the same as that of the imago. There may be two or more actual colour schemes in the whole life, both cryptic and adapted

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PLATE II. — The Bombay Locust.

Acridium Succinctum.

4. Hopper after third moult (in fourth stage), magnified five

times.

5. Hopper after fourth moult (in fifth stage), magnified three

times.

6. Hopper after fifth moult (in sixth stage), magnified twice.

The wing lobes are turned up.

7. Hopper after sixth moult (in seventh stage), magnified twice. (Reprinted from The Agricultural Journal of India.)

- (Engravrd and Prin, ,

* THE CALCUTTA PHO"!

THE BOMBAY LOCUST

ACRIDIIDiE.

75

to changes of season. Young grasshoppers hatching in the rains are frequently green to harmonize with the growing vegetation ; this often gives place to 4 ‘dry grass colour’5 in the adult which is found in October. Others which live on dry soil, on rocks, on moors, on sand dunes are coloured in shades of grey and brown with lighter markings and spots ; in nearly all the colours are dull, and though varied, evidently cryptic. In the true locusts further and more striking colour changes take place, one of which is the “swarming colour,” a vivid red, that probably facili¬ tates migration by rendering the swarm visible at a distance and enabl¬ ing all to join it. A very few are vividly coloured and undoubtedly exhibit warning colouring; this is correlated with the habit of living exposed on the plant and the young are also warningly coloured, though not

always in the same tints as the adult. In a large number of cryptically coloured forms, we find that the lower wings are bright¬ ly coloured ; in flight this colour is very con¬ spicuous and it is not difficult to follow the j erky zigzag flight with the eye; but as the wings close on the insect settling, all trace of the colour is lost, the tints of the upper wings and body blend with the surroundings, the insect sits still and vanishes before one’s eyes. There is no doubt that the bright Fig. 20— Tylotropidius didymus. colours of the lower

wings, which sometimes extend to the sides of the abdomen, are “deceptive” and materially assist in the escape of the grasshopper

76

ORTHOPTERA.

from birds or other enemies. Although the general form of the body is usually uniform throughout the family, a few are modified in con¬ nection with their habits. Thus the surface grasshoppers (Chrotogonus) which live on the soil are very much flattened, the prothorax and tegmina roughened. Some of the species that live among long grass are elongated, the body cylindrical, admirably adapted to cling to and resemble the long grass stems.

As in other Orthoptera, the chitinous integument preserves the primitive form of the lower insects, the segments being easily distin¬ guishable, the plates little differentiated. The head is of moderate size, distinct from the thorax, with large compound eyes and three ocelli. The antennae are filiform, with less than thirty joints, flattened in some species. The mouthparts are of the herbivorous type, the upper lip (la- brum) well developed, the mandibles large with cutting teeth, the maxillae and labium distinct, fitted for mastication and bearing sensory palpi. The hypopharynx is well developed as a blunt tongue-like organ on the floor of the mouth. The prothorax is large, its form and markings useful in the discrimination of genera. In one sub-family ( Tetrigince ) the pro- no turn is produced backwards as a long process between and over the wings (fig. 21). In some sub-families there is a tubercle or tooth-like

projection on the prosternum between the base of the forelegs. The meso- and meta-thorax are distinct, covered by the tegmina, which are long and narrow, opaque and variously coloured or ornamented. In many species they project beyond the abdomen, in others they are shorter. In the Tetrigince they are reduced to tiny lobes and the wings are covered by the prolongation of the pro no turn (fig. 21). In some species

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PLATE III. — The Bombay Locust.

Acridium Succinctum.

Fig 13. ) The Bombay Locust as ordinarily found when it does not ,, 14. f swarm and change colour.

(Reprinted from The Agricultural Journal of India.)

THE BOMBAY LOCUST,

. "Engraved and printed » Ifcy Cht Calcutta ■ phototype

AORIBIIDiE.

77

wings are short or reduced, the tegmina reduced to lobes or only partially developed. In the majority the wings are large, hyaline and many -veined, folding under the tegmina ; they are frequently coloured at the base with red, yellow or black. The tegmina and wings in flight function as one. The abdomen is long, the segments distinct ; it con¬ tracts and expands telescopically to a great extent in the female, in copu¬ lation being excessively retracted, in oviposition extremely elongated. The external genital organs are well marked ; the principal features of the female are the upper and lower chitinous valves, which are used for digging, the anus being above, the genital aperture below. In the male, the genital aperture is on the upper surface of the usually conspi¬ cuous ventral shield, which often ends in a point. There is a small pair of cercion.theapex of the abdomen at each side of the anus. Males and females are frequently of different sizes and also of different colours. The anterior legs are short, fitted for slow walking and clinging ; the hind legs are conspicuous by the great development of the femur and tibia ; the tibia bends back on to the femur, the apex of the former reaching the base of the latter and from this attitude the tibia kicks back, giving the impetus of the leaping motion. The tibia is outwardly set with thick spines. The femur may be specially modified to produce vibration when rubbed against the tegmen. The. inner face of the femur bears a row of knobs ; the femur is rubbed up and down against a projecting vein of the tegmen, causing the latter to vibrate. Under the tegmen, on the side of the basal abdominal segment, may be seen the auditory organ, visible as a round depression in the integument, and containing the tightly stretched tympanal membrane. Spiracles are situated on the thorax and on the membrane connecting the notum and sternum of the first eight abdominal segments. The tracheal system is character¬ ised by having bladder-like dilatations of some of the vessels, which are inflated previous to flight and while increasing the bulk of the insect, diminish its specific gravity and facilitate flight.

The life history of the known Indian grasshoppers is uniform in the main outlines but only a small proportion have been worked out. Eggs are, so far as known, universally deposited in the soil in a compact cluster, with gummy matter which hardens and compacts the mass

78

ORTHOPTERA.

(fig. 22). The number varies with the species, and all are not necessarily- laid in one mass. About sixty eggs are laid by Hieroglyphus about

100-120 by Acridium. The eggs remain in the soil for a considerable period, and loosen slightly owing to their expansion before hatching. The young hoppers have the general form of the adult, the antennae with fewer joints, the wings and internal genital system absent. The number of moults is generally from five to seven, the wings appearing as lobes at the third or fourth moult. The nymphs are active from the first ; the colouring, as stated above, may change during nymphal life or may change slowly until with the penultimate moult the colour approximates to that of the imago. The duration of the nymphal stage varies with individual species but is usually long.

Fig. 22— Chrotogonus trachy-

PTERUS, EGGS IN SOIL. xl.

It is at present impossible to generalise as to the duration of each stage of the life of these insects. Apparently most have definite seasons for reproduction, governed by climatic conditions and which are rigor¬ ously adhered to. Thus some have but one brood in a year, the three stages occupying the whole twelve months ; the Bombay Locust lays eggs in June, which hatch in July (after six weeks), the nymphal devel¬ opment is completed in late September and the imago lives until the following June : the Rice Grasshopper on the other hand remains in the egg stage from October to June and the nymphal and imaginal life occu¬ py about four and a half months. There are probably many grasshop¬ pers having only one brood yearly. Others have two, as does the Migratory Locust, the imaginal life being longest, but the two broods of about equal length. Others appear to have two broods during the rains, but the eggs laid by the second brood in November remain dormant until the following rains ; in this case the two broods are of unequal length. A number probably will be found to agree with these, having two or more broods from June to November, or from March to November, but always one hibernation brood which passes the cold weather, and generally the hot dry weather in the egg stage. A number have several broods a year

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PLATE IY. — The Migratory Locust.

Acridium (Schistocerca) Peregrinum.

15. Migratory Locust Hopper, in first stage, magnified five times.

16. Migratory Locust Hopper, in second stage, magnified four

times.

17. Migratory Locust Hopper, in third stage, magnified three

times.

18. Migratory Locust Hopper, in fourth stage, magnified 21

times.

(Reprinted from The Agricultural Journal of India.)

THE NORTH-WEST LOCUST.

ACRIDIIDiE.

79

but apparently have no regular seasons. They breed throughout the year except in the very cold weather and probably not when food is scarce. The Black Spotted Grasshopper ( Cyrtacanthacris ranacea stoll) is an example, as are the species of Chrotogonus and Atractomorpha crenulata. Hibernation and astivation appear to be passed almost wholly in the egg in the plains, only a small proportion as imagines ; this varies however with different degrees of cold and dryness in different localities. A few hibernate as imagines or nymphs in the colder parts of the plains. Apparently there is a great variety in this respect and a far larger number of species require to be worked out before one can gene¬ ralise on this point. So far as known no Acridiid is anything but herbi¬ vorous, feeding on green plants ; some have a single food plant, others several and many appear to be to some extent omnivorous. Grasses and gramineous crops are the principal food plants but flowering plants, shrubs and bushes are not exempt. Locusts have a very wide range of food plants.

Nymphs and adults live free lives, and are found wherever there is vegetation. The greater number are to be found in grasslands, in open waste lands, among low herbage. Others live among shrubs, a few on trees. Open moors, sand dunes, fallow land also contain other species and they range from the plains to considerable altitudes in the hills, with their maximum de velopment in the grasslands of the plains. This is one of the few families in which the number of purely 4 4 plains species 5 ’ is as great as the number found in submontane forest and jungle areas.

This family, being wholly herbivorous and very abundant, is one of the most injurious to Agriculture. Besides the two locusts, there are grasshoppers which attack special crops and the many species, which when abundant, attack gramineous crops. Few of these are specific pests of particular crops, they occur spasmodically and irregularly and, since grasshoppers are of universal occurrence, nothing is done to check them until they are already abundantly destructive. A distinct class of pest are the Surface Grasshoppers, species belonging to the genera Chrotogonus , Epacromia, Atractomorpha, which live on the soil and attack young crops. Little is known of which species of grasshopper are destructive since the actually destructive species is not always the

80

ORTHOPTERA.

one sent in as destructive and there is here a large field for research. The student may be cautioned against accepting the reports of injury by Acridiids in Indian Museum Notes; often an entirely harmless species is sent in, being the first one to come to hand. Not more than two locusts and six grasshoppers are actually and positively known to be injurious in India.

Whilst there is some information available as to the enemies of the two locusts, little is known of the checks on the increase of the family as a whole. The eggs of the locusts are attacked by Hymenopterous para¬ sites, the young by ground beetles ( Carabidce ), the adults by parasitic insects and the young of a mite ( Trombidium grandissimum, Koch.). An Oligochaet worm (Henley a Lefroyi, Bedd.) has been found destroying the eggs of one locust and probably attacks those of other Acridiids. Birds, monkeys and squirrels feed on locusts and the larger grasshoppers ; mynas, hoopooes and other birds eat hoppers and fossorial wasps store their nests with small hoppers. Certain fly and beetle grubs attack the eggs, but while these are probably insects of the families Bombyliidce and Cantharidce, respectively, the species concerned are not known.

The family is a very large one, the largest of the Orthoptera, but no complete list exists. It is universally distributed through the tropical and temperate zones, with a large number of species. Indian forms are largely Indo-Malavan, or have a wide distribution over Southern and Eastern Asia ; a few are European and African. In India, the species are, so far as known, widely spread and not local, though Burmah appears to have many species not found in India. No catalogue of Indian species has been compiled and the information is buried in the literature of the past century. (See page 48.) Bolivar records 100 species from a small area of South India, Brunner records 157 from Burmah. There are probably 500 recorded Indian species and at least 1,000 now existing in India. Brunner divides the family into nine sub¬ families, which are on the whole well marked. Indian species fall mainly into five of these, the characters of which are as follows : —

Tetrigince. The pronotum produced backwards over the abdomen, the tegmina lobelike, no pulvillus.

Pneumorince (African).

Mastacince. Antennae shorter than the anterior femora. Head short,

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PLATE V. — Migratory Locust. Acridium (Schistocerca) Peregrinum.

19. Migratory Locust in swarming colouration.

*20, The same in egg-laying colouration.

(Reprinted from The Agricultural Journal of India.)

THE NORTH-WEST LOCUST

ACRTDIIDiE.

81

ProscopUnce (American).

Tryxalince. — The face looking down, the vertex of the head pro¬ duced forward forming an angle. Prosternum unarmed.

Oedipodince. — The face looking forward, vertex rounded. Pros¬ ternum unarmed.

Pyrgomorphince. — Pace looking downwards, prosternum with an elevated lamina.

Pamphagince. — (Europe, Africa and E. Asia).

Acridiince. — Face looking forwards, prosternum with a tooth-like process.

The classification is best studied in the works of Brunner, de Saus- sure and Bolivar. The Tetrigince are recognizable at sight ; the Acri¬ diince and Pyrgomorphince are clearly distinct, the Tryxalince and Oedipodince are not always easily distinguished as the characters are not universal in both sub-families.

Tetrigince (Tettigides). — Small insects, of a dark-brown colour, found upon the soil and in grasslands. There are a considerable number of species which are not easy to distinguish. The sub-family as a whole are sharply marked off from the remainder of the family. Most are roughened and warty above, as are the Chrotogoni , and this with their colouring renders them difficult to see on the soil. Some are leaf-like and live among dead leaves ; all are bizarre in appearance and superfi¬ cially resemble Membracids. They are most abundant on damp soil and near water ; some are aquatic and have the hind tarsi more or less expanded to serve for swimming ; at least one species in India is aquatic, feeding on vegetation at or below the surface.

Hancock lists a total of 434 species from all parts of the world, with 34 Indian species. Scelimena (fig. 21) is a semi-aquatic genus with three Indian species, S. producta, Serv. ; S. harpago, Serv. and S. unci- nata , Serv. Criotettix has five Indian species; in this genus the inser¬ tion of the antennee is on a level with the lower part of the eye, in the former below the eye. Acanthalobus has three species. Mazarredia is an Oriental genus with four species in India. Paratettix has two Indian, two Burmese species ; Coptotettix has four Burma h species, and Saussn-

6

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82

ORTHOPTERA.

rella two, one also from India. The student should consult Hancock (Genera Inseetorum) for the genera, Brunner and Bolivar for most of the species.

Eumastacince.— The species of this sub-family are not found com¬ monly in the plains and are confined to the moister forest areas. Burr lists 23 Indian species (Genera Inseetorum) including the aberrant Chometypus fenestratus, Serv.

Tryxalince. — The genus Tryxalis ( Acrida ) includes a small number of very variably coloured insects, distinguished by their slender form, produced head and flattened antennae. One species (fig. 23) is common

Fig. 23— Tryxalis turrit a. (F. M. H.)

throughout the plains, formerly known as Tryxalis turrita, L. ; there is confusion in the present nomenclature and it is also referred to as Acrida turrita , L. and as A. exaltata , Wlk. This species varies in colour from green to “dry grass’5 colour, some with bright markings, others without; the males are smaller (36-46 rn.rm) than the females (52-64 m.m.). Tryx¬ alis lugubris , Burr is a second large species separated by Mr. Burr in his revision of the genus (Trans. Ent. Soc. London, 1902, p. 149). T. brevicollis , Bob and T. variabilisf Klug. are also Indian. Acridella is represented by A. indica , Bob and Gelastorrhmus by two species from Burmah and Sikkim, respectively.

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PLATE VI. — The Black-Spotted Grasshopper, Cyrtacanthacris ranacea (Acridium Aeruginosum).

(Reprinted from The Agricultural Journal of India.)

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Engraved and printed bg £7»e Calcutta phototupt C r

PYRGOMORPHINiE.

83

Epacromia. — A genus of small grasshoppers, common throughout India. E. dorsalis , Thunb. (fig. 24) is the most abundant species, found as a surface grasshopper destruc¬ tive to young crops. It has the unusual habit of coming to light.

There appear to be two broods yearly during the rains and hibernation takes place in the egg stage.

Oedipodinm— This is a large sub-family including a large number of species difficult to distinguish. Oedaleus (G-astro- margus) marmoratus> Thunb. is universal in the plains, marked by its brilliant orange and black lower wing. Sphingonotus , TrilopMdia,

Acrotylus , Heteropternis , Chloeo- bora and Dittopternis are also represented. Pachytylus (Locusta) cine- rascens, Fabr. (danicus, L.) is a large insect of a dull grey colour sometimes marked with brilliant green with a median keel on the prone - turn. It has a wide distribution over Southern Europe and Asia and though known to form swarms and migrate in Europe, has not been recorded as a locust in India, where it is a somewhat uncommon insect. It has been found in numbers in grasslands and there is some reason to believe that, becoming abundant in extensive tracts of grasslands in the less cultivated districts, it migrates in swarms over the country. Such swarms are apparently rare and they remain in uncultivated areas, but it will probably be definitely ascertained that the swarms of green locusts occasionally seen are of this species.

PyrgomorphincB.—. Autarches miliaris , Fabr. (Phymateus punctatus, F.) is the brightly coloured grasshopper found in the lower hill slopes ; it is black or dark green, with roughened tegmina and thorax, with yellow spots on the tegmina, the abdomen with red bands, the prothorax and head with a broad continuous yellow band. This insect when seized emits from pores in the thorax a liquid that froths up and diffuses an un-

Fig. 24- Epacromia dorsalis. (I. M. N.)

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ORTHOPTERA.

pleasant odour. The habit is a very striking one and is apt to disconcert the unwary person who does not expect it. The warning coloura¬ tion of this insect is very striking and this emission of evil smelling froth is probably a good protection. A chirping sound is produced in this species by a method unusual in the family ; at the base of each tegmen and distinct from it is a small chitinous plate, the convex curved edge of which meets the concave curved edge of the median chitinous plate at the base of the tegmina (the Scutellum) ; the former moves in an arc so that the curved edge which is striated , rubs against the striate fixed edge of the Scutellum, producing a vibration which is probably intensified by the tegmina. The sound is distinct but not loud and is probably protective as it is produced by the female.

This is the so-called 4 4 Coffee Locust ’ ’ since it occurs plentifully on coffee estates but it is practically harmless. It is recorded as destructive to coffee in Ceylon and E. E. Green has published a circular on it (Circ. Eoy. Bot. Garden, Ceylon, 111, 18). There is, in Ceylon, one brood yearly, eggs being laid in October-November and hatching in March, the nymphs being full grown by September. Several species have been made of the varieties of this species.

Poecilocera picta, Fabr. is the conspicuous Painted Grasshopper so common on the ak plant (Calotropis spp.). It is brightly coloured in blue and yellow, living openly on its food plants and evidently protected by its bad taste from birds. There are at least two broods a year, the last (in November) laying eggs