TME IMMATUR . F. CHU How To Know THE IMMATURE INSECTS CO =o a a o m o An illustrated key for identifying the orders and families of many of the immature insects with suggestions for collecting, rearing and studying them. H. F. CHU. Ph.D. Zoologist Institute of Zoology, National Academy of Peiping. Peiping, China 1946-47 Visiting Professor Iowa Wesleyan College M. C. BROWN COMPANY PUBLISHERS Dubuque, Iowa '^Uttimd'KtH Copyright © 1 949 by ^"^^^ilAtunc Sctiu H. E. Jaques Library of Congress Catalog Card Number A50-2933 ISBN 0-697-04807-1 (cloth) ISBN 0-697-04806-3 (paper) THE PICTURED-KEY NATURE SERIES How To Know The — AQUATIC PLANTS, Prescott, 1969 BEETLES, Jaques, 1951 BUTTERFLIES, Ehrlich, 1961 CACTI, Dawson, 1963 EASTERN LAND SNAILS, Burch, 1962 ECONOMIC PLANTS, Jaques, 1948, 1958 FALL FLOWERS, Cuthbert, 1948 FRESHWATER ALGAE, Prescott, 1954, 1970 FRESHWATER FISHES, Eddy, 1957, 1969 GRASSES, Pohl, 1953, 1968 GRASSHOPPERS, Heifer, 1963 IMMATURE INSECTS, Chu, 1949 INSECTS, Jaques, 1947 LAND BIRDS, Jaques, 1947 LICHENS, Hale, 1969 LIVING THINGS, Jaques, 1946 MAMMALS, Booth, 1949, 1970 MARINE ISOPOD CRUSTACEANS, Schultz, 1969 MOSSES AND LIVERWORTS, Conard, 1944, 1956 PLANT FAMILIES, Jaques, 1948 POLLEN AND SPORES, Kapp, 1969 PROTOZOA, Jahn, 1949 ROCKS AND MINERALS, Heifer, 1970 SEAWEEDS, Dawson, 1956 SPIDERS, Kaston, 1952 SPRING FLOWERS, Cuthbert, 1943, 1949 TAPEWORMS, Schmidt, 1970 TREMATODES, Schell, 1970 TREES, Jaques, 1946 WATER BIRDS, Jaques-Ollivier, 1960 WEEDS, Jaques, 1959 WESTERN TREES, Baerg, 1955 Printed in United States of America INTRODUCTION NSECTS constitute the largest group of the animal kingdom. There are over seven hundred thousand species which have been named and described and still a large number of new species is being added to our knowledge every year. Because of the great diversity of their behavior and habits, their study is filled with interest. From the econo- mic point of view, some insects are considered beneficial and others injurious to human beings. The better we know our insect enemies and insect friends, the better are our chances of anticipating protections or of preparing and conducting our defenses against them. Insects are highly different in their young and their adult stages. For example, the butterflies fly in air and feed on nectar of flowers while their caterpillars live on plants and chew these coarse tissues; mosquitoes suck blood while their larvae dwell in water; many moths do not feed at all but their larvae do great damage to our crops. There are thousands of differences in their ways of living and also of the body structures between insect parents and their children. We need to know the adult insects and it is also necessary to know the imma- ture insects. From either the economic standpoint or the evolutionary aspect the more we know of the immature stages the better we un- derstand the adult insects. Unfortunately our knowledge of the immature insects is still far away from complete. Much work must still be done in this interesting and very important field. This book is compiled from the available literature and designed to make it as easy as possible to acquire a ready knowledge of the immature insects. It contains a number of illustrated keys for identification of these insects to orders and their principal families. For advanced study, important references are giv- en. In attempting this book the author feels like an explorer entering an uncharted region. At best there will be ommissions and mistakes. I shall be grateful for any corrections or constructive suggestions to put into later printings of the book. N The excellent instruction of Dr. W. P. Hayes, Professor of Entomol- v)ogy. University of Illinois on the immature insects during the time HOW TO KNOW THE IMMATURE INSECTS when the author was a student in his classes has made the book possible. Dr. H. E. Jaques, Professor of Biology, Iowa Wesleyan College, has given encouragement and invaluable suggestions. My wife, Y. S. Liu has helped with drawings and in many other ways. The author wishes to thank them most sincerely for all their kind help. Peiping, China January 1, 1949 4^ -^^ /^ ":> We have found Dr. Chu not only a thoroughly trained Entomologist and an excellent teacher but also a most faithful friend. He has given much time and thought to the preparation of this manual in a com- parative new and difficult field. We feel certain that students of in- sects will find it highly helpful. CONTENTS Page What Are Immature Insects 1 The Importance of Immature Insects 3 What Immature Insects Look Like 6 Where to Collect Immature Insects 19 How to Collect Immature Insects 21 How to Rear Immature Insects 26 Pictured-Keys to Orders of Immature Insects 28 Pictured-Keys to FamiHes 54 Order Protura 54 Order Thysanura 55 Order Collembola 58 Order Plecoptera 59 Order Ephemeroptera 62 Order Odonata 67 Order Orthoptera 69 Order Coleoptera 72 Order Hemiptera 129 Order Homoptera 135 Order Neuroptera 140 Order Trichoptera 146 Order Lepidoptera 149 Order Diptera 189 Order Hymenoptera 210 Some Important References 217 Index and Pictured Glossary 224 f *i *4 ^t A *<^ ^ >^ >^ < — t WHAT ARE IMMATURE INSECTS DEVELOPMENT OF INSECTS. — When an egg and a sperm unite to form one cell fertilization results and the embryo begins to develop within the eggshell. This is called embryonic development and all that takes place after hatching or birth is postembryonic development. The life cycle is completed when the insect is fully grown and capable of producing young. METAMORPHOSIS. — The term metamorphosis is derived from the Greek words, nieta, change, and morphe, form, designating a change of form. The plural is metamorphoses. It is defined as the ser- ies of changes through which an insect passes in its growth from the egg through the larva and pupa to the adult, or from the egg through the nymph to the adult. a) Gradual or simple metamorphosis. — In many insect species the young are very much similar to the adult externally, except for the complete absence of wings. But after a period of growth the wing may appear, attached to the out- side of the body as small wing pads. The more developed the young insect becomes, the more it resembles its parents. Such a development is called a gradual or simple metamorphosis. The young of such insects are called nymphs. They commonly have the same habits as their parents and the nymphs and adults fre- quently feed together. An example is the aphids where both adult and young are habitually found associated on the same plant. Grasshop- per nymphs and adults both eat grasses and clovers and may be found hopping about together in the pastures. The insects of gradual or simple metamorphosis include the orders Plecoptera, Ephemeroptera, Odonata, Embioptera, Orthoptera, Isoptera, Dermaptera, Thysanoptera, Corrodentia, Mallophaga, Anoplura, Hemiptera and Homoptera. All these insects are collectively known as the Heterometabola. b) Complete or complex metamorphosis. — In this type of meta- morphosis, the young are very different from their adults. There are no external traces of wings. The young are known as larvae and the adult is preceded by a pupal stage. The insects having this type of metamorphosis are collectively called the Hoio- metaJboia and include the orders Coleoptera, Neuroptera, Tri- choptera, Lepidoptera, Mecoptera, Diptera, Siphonaptera, Strep- siptera and Hymenoptera. Fig. 1. The life stages of chinch bug, Blissus leucopterus (Say) : a-e, 1st to 5th instar nymphs; f, adult; g, eggs. (U.S.D.A.) 1 HOW TO KNOW THE IMMATURE INSECTS Fig. 2. The life stages of Anomala konsano Hayes Cr Mc- Colloch: a, egg; b-d, 1st to 3rd instar larvae; e, pupa; f, adult. (Redrawn from Hayes) c) No metamorphosis or Ametabola. — The insect of this type of metamorphosis have no distinct external changes in development, except in size. When the young hatches from the egg it resembles its parents and scarcely shows any changes in appearance during the course of development. This is especially true of a small number of wingless insects belonging to the orders Protura, Thysan- ura and Collembola. These insects shed their outer coat (molt) from time to time to permit more comfort- able growth, but all of these successive stages appear very much the same except in size. Some would call these immature stages "nymphs" but "young" seems to be a more accurate and preferred term. Fig. 3. a, Protura; b, Thysanura. HOW TO KNOW THE IMMATURE INSECTS Me tamo rpho sis Life Stage Heterometa'bola or Gradual metamorphosis Egg Nymph Adult Holometabola or Complete metamorphosis Egg Larva Pupa Adult Ametabola or No metamorphosis Egg Young Adult Fig. 4. Metamorphosis and life stages. IMMATURE INSECTS. — From the previous figure of the insect life stages, insects are seen to have two or three stages before they become adult or imago. The stages, egg, young (nymph or larva) and pupa are the immature stages of insects. We must consiaer all the life stages which precede the adult stage. INSTARS. — Every insect during its growth sheds its skin one or more times. This process is known as a mouh or ecdysis. The cast skin is termed the exuviae (this term does not exist in the singular). The intervals between moults are known as stages or stadia (singular, stadium), and the form assumed by an insect during a particular sta- dium is termed an instar. When an insect issues from the egg it is said to be in its iirst instar; at the end of this stadium the first moult occurs and the insect then assumes its second instar, and so on. The final instar is represented by the fully mature form and is known as the aduh or imago. Ist moult 2nd moult hatch 1st ^instar > 2nd instar > 3rd instar EGG ^MIHHMHIiM^ LARVA ^■■■■■H^HM^HM nth moult 3rd moult emerge pupate ♦-(n+l)th instar^^ 4th instar < ADULT ^H-H^i FUPA ^■»MMMMHiHHi^HiiiH^MiiHHa^Ha^^^»iMi NTMBER OF INSTARS = number of moults + 1 Fig. 5. Life stages and instars. THE IMPORTANCE OF IMMATURE INSECTS NUMBER OF SPECIES OF INSECTS. — According to Z. P. Metcalf (Ent. News 51: 219-222. 1940), approximately 1,500,000 species have been described during the period from 1758 to 1940. This would make the insects occupy almost eighty per cent of the species of the whole animal kingdom. HOW TO KNOW THE IMMATURE INSECTS IMMATURE STAGES OCCUPY A LARGER PART OF THE LIFE CYCLE. — The egg stage usually lasts but a few days, sometimes even shorter, or the egg may hatch before it is laid, as is the case in the aphids. Many insects hi- bernate in the egg stage in which event the egg period may last several months. The growing stage is usual- ly much longer than other stages. The nymph of the periodical cicada, Magici- cada septendecim (L.) Lives underground from 13 to 17 years as compared with the 30 or 40 days of its adult's life and 6 to 7 weeks of its egg stage. While some May- flies live as adults for only a few hours, their nymphal stage is believed to occupy three years. Many insects spend their winter time in Fig. 6. Life cycle of the Japanese beetle, Popillia japonica Newman. the pupal stage. In general, insects spend considerably more time in their immature stages than they do as adults. LARVA AND NYMPH ARE HEAVIER FEEDERS. — When a survey of the feeding habits of insects is made, the nymphs are usually found to take the same kind of food as their adults. Larvae on the other hand, usually feed differently and consume much more than their adults. Take the order Lepidoptera as a good example; the caterpillars eat a large quantity of food while a good number of moths do not feed at all. ANIMAL EVOLUTION AND ADAPTION. — The zoological position of some animals that are of degenerate form in the adult stages has been established only by study of their embryonic and larval stages. The larvae of barnacles show that these animals belong among the crustaceans, and the peculiar parasitic barnacle, Sacculina can be recognized as a crustancean only during its larval existance. Likewise, the tunicates were found to be Chordates only by a study of their larval characteristics. The adults of the Coniopterygidae look like aphids but are regarded as Neuropteia because of the structures of their larvae. The degenerate form of the aduhs gives no clue to their real position among animals. Among insects there are many highly interesting points to study in their evolution and adaptation. A knowledge of the immature stages makes for a much clearer understanding in both of these fields. HOW TO KNOW THE IMMATURE INSECTS INSECT CONTROL. — The injurious insects give us a clear idea of the importance of immature insects. It is the larvae of the Codling moth, Carpocapsa pomonella Linne, for example which feed on our apples, not the adult moths. The maggots of the Mediterranean fruit- fly, Ceratitis capitata (Wiedeman), do serious damages to fruits, but the adult flies except for laying eggs are quite inoffensive. Note also the Gypsy moth, Porthetria dispar (L.), the Browntail' moth, Nygmia phaeorrhoea (Donovan), and many Wire worms (Elateridae), White grubs (Scarabaeidae), Cut worms (Noctuidae); their larvae cost us millions of dollars every year. We need to know the morphological structures, life histories and habits of the immature insects in order to successfully conduct measures for their control. WHAT IMMATURE INSECTS LOOK LIKE EGGS Insects develop from eggs which differ greatly in size and shape in different species. As a rule, insects tend to lay eggs proportionate to their own size. The smallest known eggs are those of the CoUembola. The eggs of one of the small headed flies measure 0.15 by 0.18 milli- meter. The eggs of the clover seed midge and of the Tingidae are also minute. The other extreme is found in the eggs of the giant silk moth, those of the polyphemus moth being 3 millimeters in diameter. The shapes of insect eggs are described in the following: (a) Flat and scalelike (Fig. 7). — Take for example the eggs of the codling moth and the orien- tal fruit moth. Fig. 7. Eggs of the cod- ling moth, Corpocopso pomonella L. (b) Spherical (Fig. 8). — The eggs of many spe- cies, such as the swallow-tail butterfly, the green June beetle and many other Scara- V -J 1. • 1 Fig. 8. Eggs of a baeidae are spherical. butterfly. (c) Conical (Fig. 9.) — The eggs of the imported cabbage worm, Pieris rapae (L.) and the _. _ t, , .. violet tip, Poiygonia interrogationis Fab., are Fig. 9. Eggs of the ■ i . v j , f -j j foil army//orm, conical m shape and deeply ridged. Lophygma frugiper do (Smith Cr Abbott). HOW TO KNOW THE> IMMATURE INSECTS (d) Elongate (Fig. 10). — Many eggs are elongate, as for example, the eggs of leafhoppers, tree- hoppers and tree crickets. Eggs of this type are often inserted in nar- row cavities such as hollow grass stems or in burrows made with the ovipositor or lend ,^r- themselves readily to being laid in compact Fig. 10. Eggs: a, sugar- j -a r- cane leafhopper, Perkin- arOUPS sielia saccharicida Kirk- ^ ^ cidy; b, Mexican bean beetle, Epilachna vorives- tis Mulsant; c, housefly, Musca domestica L. (e) With appendages (Fig. 11). — The eggs of a water scorpion have eight or more filaments . \ y, radiating from the upper rim. Pentatomid ^%i^;v7ii eggs are usually beset with a circle of spinej ^ ' ' around the upper edge. Reduviid eggs have a definite cap at one end. The poultry louse has a striking egg, — white and covered with glass-like spines. The free end of this egg is furnished with a lid which bears at its apex a long lashlike appendage. Fig. 11. Eggs: a, Podi- sus maculiventris Say; b. Mayfly, Tricorythodes al- lectus (Needham). m' % a Fig. 12. a, Egg of the Western 12-spot- ted cucumber beetle; b, egg sculpture (From mass; c-d, of egg. Webster) (f) With sculpturing (Figs. 12 and 13).— The sur- faces of insect eggs may be entirely smooth or with imbricated designs. Eggs that are laid in wood, leaves, or in the ground are frequently without sculpturing. The eggs of Curculionidae and Scarabaeidae are per- fectly smooth. On the other hand, many eggs are reticulated or strikingly marked. These reticulations are the imprints of the cells of the follicular epithelium. The eggs of the flower flies are chalky white and microscopically sculptured. The leaf-mining flies (Genus Pegqmya) usually have eggs that are well marked by hexagonal or poly- gonal areas. The eggs of many butterflies and moths such as Pieridae, Noctuidae, etc. are deeply ridged and strongly sculptured. Fig. 13. Peridroma sou- cia Hubner: a, egg; b, egg mass. HOW TO KNOW THE IMMATURE INSECTS NUMBER OF EGGS. — The sheep-tick and the true female of many aphids, for instance, produce but a few eggs (as few as 4). On the other hand, the egg mass of the dobsonfly may contain 3,000 eggs, and a parasitic fly, Pterodontia Uavipes (Cyrtidae) has been reported as laying 3,977 eggs. The social insects lead the list. A termite queen may lay 1,000,000 eggs during her Hfe. Queen ants and queen honey bees likewise are highly prolific. WHERE THE EGGS ARE LAID — The whole story of where insects Fig. 14. Eggs: a, Boll-weevil parasite, CerGmbycobius cyaniceps; b Boll- weevil parasite, Eurytoma tylodermatis Ashrri.; c. Range caterpillar- d. Asparagus beetle, Crioceris asparagi (L.); e, egg moss of Culex pungens Wiedemann; f, egg mass of the gypsy moth, Pofhetrio dis par (L.); g, Rosy apple aphid; h, apple leaf roller; i, grasshopper- J, sheep louse; k, Hypoderma lineata (De Villiers); I, katydid- m Snow tree cricket; n, Oeconthus niveus (De Geer) / / / HOW TO KNOW THE IMMATURE INSECTS lay their eggs is a complicated one, but very interesting. Insect eggs are generally laid in situations where the young, upon hatching, may readily find food. Species that feed upon foliage usually lay their eggs upon leaves of the correct plant. The ability of adult to recognize the right species of food plant for its offspring often seems remarkable. Aquatic insects lay their eggs in or near the water. Parasites general- ly lay their eggs upon or within their host. Some flower flies lay their eggs in clusters of aphids or other soft-bodied insects. The Mallophaga and Anoplura lay their eggs upon the hair or feather of their hosts. There are also many special cases. Some insects lay their eggs upon foliage or in the ground and the young are compelled to seek their hosts. The twisted-winged insects (Stylopids) often lay their young upon plants where they must wait until certain solitary bees visit these plants. The young then grasp the legs of the bees and are carried to nests where they find theii hosts. The eggs of walkingsticks lie dor- mant beneath leaves or other debris upon the ground. With the ap- proach of Spring, the eggs hatch and the nymphs must find the leaves of their host plants. Insects such as leafhoppers and aphids, many of which feed upon herbaceous annual plants during the summer, seek woody plants on which to lay their eggs when winter approaches. Many leaf-mining insects of the orders Lepidoptera, Hymenoptera, Coleoptera and Diptera insert their eggs into wood, leaves, fruits and seeds, thus offering ready access to food for the young when they hatch. The Fruit Flies and many Snout Beetles insert their eggs direct- ly into the fruit in which their larvae will develop. The tree crickets, treehoppers and leafhoppers lay their eggs within woody plants for protection of the eggs. Some Chalcids oviposit in seeds. In- sect eggs are sometimes car- ried by the adult for better pro- tection. The Hydrophilid beetles of the subfamily Sphaeridiinae carry the eggs attached to their hind legs. Certain Mayflies may carry two eggs adhering to the posterior end of the body - until opportunity is found to drop them into the water. a, Mantid; b, cross-section Reaches often carry an egg c, phosmid; d, ^^gg (ootheca) at the tip of the abdomen. The females of the Fig. 15. Oothecoe of mantid ootheca German cockroach. 8 HOW TO KNOW THE IMMATURE INSECTS Fig. 16. Eggs on the back of male insects: o, Phyl- lomorpha laciniata; b. Western water bug, Abe- dus sp. live in the ant's nest (called inquilines). giant water bugs, Belastoma, Serphes and Abedus deposit their eggs on the back of males where they remain until hatched. Some most interesting cases are those insects which impose upon other species. The water boat- man, Ramphoconxa acuminata, attaches its eggs to the body of a crayfish. The human bot fly, DermafoJbia hominis, uses the mos- quito to transport its eggs to man. The bot- fly visits marshy places where mosquitoes are emerging. It seizes a mosquito and de- posits 10 to 12 eggs on the abdomen and legs of the mosquito, after which it releases its hold. When the mosquito visits man, the warmth of his body causes the botfly eggs to hatch and the young maggots dig into the flesh of the victim. The females of the Euro- pean beetle, Clythra quadrimaculata, deposit their eggs on the foliage of birch or other trees. These are covered with excrement and resemble small bracts of the plant. The ants pick these up apparently mistaking them for bits of vegetable refuse, and take them into their nests. When the eggs hatch the larvae as guests The ravenous larvae known as aphid lions hatch from eggs held erect on slender threads (fig. 17) and are thus supposedly prevented from eating the unhatched eggs. Fig. 17. Eggs of the ophid lion. NYMPHS The term nymph is obtained from the Greek word meaning bride or maiden. In mythology, a nymph was one of the inferior deities of Nature, represented by a beautiful maiden, who inhabitated the mountains, forests and water. In entomology, a nymph is one of the immature instars of insects with a gradual metamorphosis. The im- mature stages of Orthoptera, Isoptera, Hemiptera, Homoptera, Thysan- optera, Anoplura, Dermaptera, Mallophaga and Corrodentia are known as nymphs. Nymphs have certain characters in common. The wings develop on the exterior of the body (some in the later instars). Com- pound eyes are usually present, and the species are mostly terrestrial. HOW TO KNOW THE IMMATURE INSECTS They have no resting stage (pupae) before the aduU is reached. The body form and structures as well as the feeding habits are generally similar to those of the adult. Fig. 18. Nymphs: a, grasshopper; b, pear psylla, Psylla pyricola Fors- ter; (Redrawn from Conn. Agr. Expt. Stc. ) c, Western crick- et, Anabrus simplex Haldeman; d, plant bug; e, AAallophaga; f, Anoplura; g, aphid. In the Thysanoptera, there is no indication of wing pads until the second or third instar. In Corrodentia, the nymphs lack wing pads even in species that develop wings. In Thysanoptera and the male Fig. 19. Bean thrips, Hercothrips fasciatus (Pergonde): a, egg; b, newly hatched nymph; c, mature nymph; d, prepupa; e, pupa. (U.S.D.A.) Aleyrodidae and Coccidae, there is what appears to be a pupa. In the male Coccidae, even a cocoon is formed. The nymphs of Noto- nectidae, Corixidae, Belostomidae, Nepidae and some other smaller families of Hemiptera are semi-aquatic. They descend beneath the waters and remain there for a considerable period of time, out they are air breathers. 10 HOW TO KNOW THE IMMATURE INSECTS NAIADS In mythology, a naiad was one of the nymphs believed to live in, and give life and perpetuation to lakes, rivers, springs and fountains. In entomology, the term naiad is applied to the nymph with aquatic habits. There are al- together only three or- ders of insects which possess immature stages that are termed naiads. These are the Plecoptera, Ephemerop- tera and Odonata. The naiads have some char- acters in common. All naiads are aquatic (ex- cept a few exotic spe- cies); they have closed spiracles, breathe by means of gills, and have mouth parts of the chewing type. Most of them are predacious, but the naiads of Ephemeroptera are believed to be herbaceous. Naiads are generally quite uniform in appearance. The legs are long, the body is flattened and campodeiform and they are very ac- tive in water. The naiads of Plecoptera and the Ephemeroptera have conspicuous caudal filaments, varying from two to three in number. In the damselflies (Zygoptera), the caudal appendages are modified into leaf-like form and known as tracheal gills. Tracheal gills are located on various parts of the body. In Plecoptera, they are usually lo- cated on the underside of the thorax, although some species have gills on the head or on the abdomen. In Ephemeroptera, the gills are located on the abdomen. In the dragonflies, the rectum is modified to form a tra- cheal gill chamber. In the damselflies, there are three plate-like gills at the posterior end di the abdomen. Fig. 21. Rectal tracheae of dragonfly. Fig. 20. Naiads: damsel fly (Odonata); b, stonefly (Plecoptera); c, Mayfly (Ephemeroptera). LARVAE The term larva is derived from the Latin word for mask, having reference to the ancient belief that the adult form was masked or ob- scured in the larva. In entomology, the larva applies to the immature stage between the egg and the pupal stages of the insects with com- plete metamorphosis. There are several characters in common. A lar- va has no trace of wings and compound eyes are never present. The 11 HOW TO KNOW THE IMMATURE INSECTS shape and the appendages ordinarily are very different from those of the aduh; while the body is often soft, thin skinned, or weakly sclero- tized. TYPES OF LARVAE 1. Campodeiform (Fig. 22), — The char- acteristics of a campodeiform larva are flattened body and long legs with cerci or caudal filaments usually pre- sent. The larvae of most of the Neu- roptera, the Trichoptera, many of the Coleoptera, Dytiscidae, Carbidae, Sta- phylinidae, and the naiads of Plec- optera, Ephemeroptera and Odonata are campodeiform. Fig. 22. Larvae: o, ground beetle, Pterostichus sp.; b, Dobsonfly, Corydalus cornutus (L.) Carabiform (Fig. 23). — This is a modified form of the campodeiform in which the body is flattened but the legs are short- er. Generally there are no caudal fila- ments. The majority of the Chry some- lid beetles and many other Coleoptera (Lampyridae, Carabidae, Melyridae) ex- hibit this type. Fig. 23. a, Caraboid instar of meloid larva; b, saw-toothed groin beetle, Oryzaephilus suri- namensis (L.) 12 HOW TO KNOW THE IMMATURE INSECTS 3. Eruciform (Fig. 24). — This type of larva is cylindrical, the thoracic legs and prolegs are present and the head is well formed. It is well illustrated in the Lepidoptera, Tenthredinidae and Mecoptera. Fig. 24. Larvae: a, alfalfa caterpillar, Eurymus eurytheme (Boisduval); b, tomato hornworm, Protoparce sexta (Johnssen); c, tussock moth, Hemerocampo vetusta Boisduval; d, tomato fruitworm or corn earworm, Heiiothis obsoleta Fabricius. (U.S.D.A.) 4. Scarabaeiform (Fig. 25). — The acarabaeiform larva is cylindrical and curved in U-shape with a well developed head and usually with thoracic legs but without prolegs. There are a pair of spiracles on the prothorax and eight pairs of abdominal spir- acles. This type of larva is typical of the Scarabaeidae. It is also represented by the ^ ^^ . ^ , . u« «. Bruchidae, Ptinidae, Anobiidae, Fig. 25. Larvae: a, Anomalo konsana Hayes & McColloch; b, clover leaf weevil, Q^d Other Coleoptera. Hypero punctata (Fab.) ^ Elateriform (Fig. 26). — These larvae are cylindrical in shape with a thick tough body wall. The setae are much reduced, the legs are usually present but short. They resemble both the vermiform and carabiform larvae. This type is well represented by the Elateri- dae, Tenebrionidae, AUeculidae, Ptilodactylidae and Eurypogonidae. Fig. 26. False wireworm, Eleod- es letcheri von- dykei Blaidell. 13 HOW TO KNOW THE IMMATURE INSECTS Fig. 27. a, Molamba lonota l-ec. ,< Redrawn from Boving and Craighead) b, Sadd e- badk slug caterpillar, Sobine stimulea Clemens. Platyform (Fig. 27).— This type is short, broad and extremely flat. The legs are short, inconspicuous or absent. They are found in the genera Microdon and Xanthogrammci of syrphid larvae, the larvae of some slug caterpillars and those of the water pennies, Pse- pheus, hister beetles, etc. 7. Vermiform (Fig. 28).— The larvae of this type are more or less wormlike. This designation is indefinite but is usually considered to include larvae that are cylindrical in shape, elongate and with- out locomotive appendages. Most of the larvae of Diptera are like that. This ,. ,,..^ , . is also true of the larvae of woodboring l^i"'' ' beetles, some sawflies and the flea beetles of the genera Systena and Epi- trix. The larvae of fleas and many para- sitic Hymenoptera also belong to this type. Fig. 28. Larvae: a, cabbage root mag'got, Hylemyio bros- sicae (Bouche); b, buffalo- gnat, Simuiium pecuarum Riley; c, common cattle grub, Hypoderma lineatum (De Villiers) under host skin. (U.S.D.A.) 8. Hypermetctmorphosis (Fig. 29). — This is a kind of complex meta- morphosis in which there are several types of larvae, including: a minute active first instar, a more or less robust and sluggish second instar, and a similar but legless third instar. It is represented in the Neuroptera (Mantispidae), Coleoptera (Meloidae, Carabidae, Sta- phylinidae, Rhipiphoridae), Strepsiptera, parasitic Diptera (Acrocera- tidae, Bombyliidae, Nemestrinidae, Tachinidae), and Hymenoptera (Ichneumonidae, Pteromalidae, Perilampidae). The larvae of this type often have special names. The first instar of Meloidae, Strep- siptera and Mantispidae are called tiiungulins. They receive this name because the legs have three claws. The fifth instar of Meloidae 14 HOW TO KNOW THE IMMATURE INSECTS is called a coaictate larva or a pseudopupa. The first instar of Platygaster, a pcorasite of the Hessian Fly, resembles a crustacean Fig. 29. Life srages of Epicauta vittoto Fabricius. and is called a naupWiioxm larva. The first instar of Perilampus, a secondary parasite of the fall webworm, is called a planidium, mean- mg a diminutive wanderer. COMMON NAMES OF LARVAE The importance of common names has been emphasized by many Entomologists in recent years. We wish we could have common names or all the more important insects. Only a few orders now have com- non names. The larvae of Lepidoptera are known as cateTpillars. The erm gzubs is applied to the larvae of Cpleoptera. Maggots indicate me larvae of Diptera, Cyclorrhapha and Caddiswoims the larvae of |Trichoptera. A number of common names have been applied to the larvae of certain families: the Geometridae are called inchworms or jpeasuring worms; the LimacodMae are known as siug caterpillars; the Psychidae are called bagworms; the Chrysopidae are named aphid- fions; the Myrmeleonidae are known as an/-iions. The Elateridae are called wireworms and the Sphingidae are known as hornworms. Some common names are derived from the larval habits, such as HOW TO KNOW THE IMMATURE INSECTS cu Fig. 30. Larvae: a, Anopheles sp.; b, ground beetle; c, Protyphylox sp.; d, sawfly larvae; e, aphid lion; f, Stenophylax sp. (In part frorr. U.S.D.A.) leaf rollers, leaf miners, casebearers, webworms, tent caterpillars, leaf skeletonizers, cutworms, armyworms, borers, leaf tiers, loopers, leaf folders, gall makers, etc. Names of the hosts are usually used in in- dicating the insects of that particular host, for example, corn borer, tobac- co hornworm, etc. The part of the host which the insects attack is also used in the common names of the larvae, such as the elder shoot borer, pink bollworm, tomato fruitworm, etc. Common names, unless standardized, are often confusing. Fig. 31. The formation of the bag in early stages of Thyrido- pteryx ephemeraeformis Hay- worth. (U.S.D.A.) The common names of insects with economic importance have been standarized by the American Association of Economic Entomologists which include a number of names for the specific larvae. t>UPAE The term pupa, derived from the Latin word meaning baby or child, was proposed by Linnaeus on account of its resemblance to a papoose or baby bound in garments. The term was first used in con- nection with the chiysalis of Lepidoptera. The pupa is defined as the resting stage or inactive period of all insects with complete metamor- 16 HOW TO KNOW THE IMMATURE INSECTS phosis, the intermediate stage between the larva and the adult. Anoth- er term prepupa refers to the last larval instar of some insects which retain the larval form and mobility but cease to feed. This condition exists in many orders of insects, notably the Diptera, Hymenoptera and Coleoptera. TYPES OF PUPAE. — The pupae of insects can be classified with reference to the degrees of freedom of the appendages. 1. Obtect (Fig. 32). — If the appendages are closely appressed to the body, it is said to be an obtect pupa. This is a common type in the Lepidoptera, in many of the Coleoptera, and in more primitive Diptera. Pupae of this type are covered with a tight-fit- ting, more ©r less transparent skin which holds all the parts except the end of the abdomen practically cl '^ immovable. Chrysalis is a term often appHed to the Fig. 32. pupae: a, pupae of the Lepidoptera, especially of the butter- ilS^ tos o'^'e e a'n*o fhes, and by some would be restricted to those bSS:o'^^/»ornworm' pupae bearing markings of silver or gold. q^emaVu\l*a**Ha worth. 2. Exarate (Fig. 33). — When the appendages are not closely appres- sed to the body but are free, it is said to be an exarate pupa. The Neu- roptera, Tricho p t e r a, most of the Coleoptera and a few of the Lepi- doptera (Tischeriidae) have exarate pupae. Fig. 33. Pupae: a, Colorado potato bee Leptinotarsa decemlineata (Soy); Hesperophylax Ep. 17 HOW TO KNOW THE IMMATURE INSECTS 3. Coarctate (Fig. 34). — The appendages are not visible at all and are obscured by the larval skin before the last moult, in the coarctate pupa. This type is found in the more specialized Diptera (Cyclorrhapha) and in certain Coccidae and Stylopidae. The length of time in which an insect remains in its pupal state is highly variable. Much goes on within the pupal case before the adult is ready to emerge but the whole process moves so rapidly with some species that the insect remains as a pupa for only a few days. Many insects pass the winter or other unfavorable time in the pupa stage. When their growth is com- ^^9-^ ^agSt^^Hy- pleted many larvae travel for a day or two thus scat-'^^y'^^g^'*'**'*'***® tering the species and lessening the chances for total loss of a brood. These larvae usually select some pro- tected spot before settling down. PROTECTION OF PUPAE. — Most pupae are concealed in one way or another from their enemies, and also from such adverse influences as excess of moisture, sudden mark- ed variations of temperature, shock and other mechanical disturbance. Pro- vision against such influences is usual- ly made by the larva in its last instar. Many lepidopterous and coleopterous larvae burrow beneath the ground and there construct earthen cells in which to pupate. The larger number of insects, however, construct cocoons which are special envelopes formed either of silk or of extraneous material bound togeth- er er by means of threads of that sub- stance. Thus many wood-boring larvae utilize chips. Larvae which transform in the ground select particles of earth. Many Arctiid larvae use their body- hairs and Trichoptera use pebbels, veg- Rig. 35. Cocoons: a, braconid cocoon; b, empty braconid co- coon; c, cocoon of the clover- leaf weevil; d, cocoon of the aphid lion. (U.S.D.A.) 18 Fig. 36. Cases of the bagworm, Thyridopteryx ephemeraefor mis H a - worth. HOW TO KNOW THE IMMATURE INSECTS etable fragments, etc., these larval cases functioning as cocoons. In these instances the substances are held together by means of a warp of silk and worked up to form cocoons. A large number of other insects, including some of the Neuroptera and Tri- choptera, many Lepidoptera and Hymenop- tera and the Siphonaptera, utilize silk alone in making their cocoons. Among the Tenthredinidae, cocoons of a parch- ment-like or shell-like consistency are fre- quent: in some cases the outer cocoon en- closes an inner one of more delicate tex- ture which may be called a double cocoon. The naked pupae of but- terflies are suspended by silk on the cremaster at the caudal end of the abdomen. In the Diptera (Cyclorrhapha), in- stead of spinning a silken cocoon or constructing a case of extraneous material, the larva prac- tices an interesting economy by retaining about itself one of its own cast, dry skins to form a case called a puparium. This next-to-the-last lar- val skin is not discarded at the time of pupation but is retained until the adult breaks out of the pupal skin. Fig. 37. A butterfly pupa. WHERE TO COLLECT IMMATURE INSECTS Insects are so highly diversified in their food and ways of living that one may find at least a few insects almost any where he looks. When we consider their habits the insects fall into groups which may be rather definitely located. A. CHARACTERIZED HABITATS: 1. Aquatic Insects. — Those insects that dwell in water or are more or less closely related with water are said to be aquatic. About five per cent of all the insects are aquatic and still another three per cent are closely related with water. In a strict sense,* the truly aquatic insects are those which employ gills to separate the oxygen from the water in which they live. Other insects "obtain their oxygen from the air but because they are closely related with water are said to be semiaquatic insects. If we take a count of the insect orders, almost half of them have aquatic or semiaquatic species. The Ephemeroptera, Odonata, Plecoptera and Trichoptera, with rare exceptions, are strictly aquatic. 19 HOW TO KNOW THE IMMATURE INSECTS The Neuroptera, Hemiptera, Diptera, Lepidoptera. Coleoptera and Hymenoptera are only partly aquatic. Some Collembola live on the surface of water. 2. Phytophagous Insects. — Most insects feed on plants. We can find them on or in the plants. Others in like manner feed in dead woods or decaying plant materials. All these are said to be phytophagous. 3. Parasitic Insects. — Those insects that secure their food by living within other animals are known as endoparasites. Ectoparasites live and feed on other animals from the outside as with lice. Many insects live within dead or decaying animal and plant materials and are said to be sapiophagous. 4. Subterranean Insects. — These insects exi.st beneath the surface of the soil. Most of the orders contain some species with subterranean habits. Remarkable examples are ants, termites, social wasps and bees which live together of their own. Numerous insects lay their eggs in the soil, such as the grasshoppers, earwigs, beetles, flies, etc. Among the Coleoptera, the Cicindelidae, Carabidae, Scarabaeidae, Meloidae and Elateridae are outstanding examples. With the Diptera, the Tipu- lidae, Bibionidae. DoUchopodidae, Rhagionidae, Empididae, Asilidae, Bombyliidae and Anthomyiidae commonly hide the eggs within the ground. Lepidopterous larvae and pupae frequently hibernated in the soil. Comparatively few nymphs dwell in the soil except certain root- feeding Aphididae and Coccidae and the immature mole crickets. The cicada nymphs on the other hand spend a long time underground. B. SOME CHARACTERISTIC MARKINGS: 1. Damaged Plants. — Defoliated plants, skeletonized or partial eaten leaves, holes bored in plant stems or in fruits, etc., are good indica- tions for locating the insects which did this damage. 2. Associated Animals. — When a collector sees busily working ants, he can find aphid colonies near by. From the noise of bees or flies, we can often find their nests or their larval breeding places. On the host animals, we can usually find predators and parasites. 3. Sweet Secretions. — A number of insect families, such as the Chir- midae, Aphididae and Coccidae give off a molasses-like sweet secre- tion known as "Honey dew". This is easily observed and helps to locate the insects producing it. 4. Insect feces. — Many caterpillars for instance eat such large quantities of coarse foods and discharge such large amounts of waste material from the digestive tract as to give a clue to their presence. Furthermore, from the characteristic shape of the feces, certain species can be identified. 5. Abnormality of Plants. — Not only the abnormal growth of plants but also the malnutrition of plants can lead us to find the insects re- 20 HOW TO KNOW THE IMMATURE INSECTS sponsible for these stunted conditions. The gall-insects and leaf min- ers are readily located within the galls and the mined leaves. Many- other insects can be found on malnutritive plants even though the in- sect pests are feeding underground. Fig. 38. Q, Wool sower gall, Andricus seminator Harr.; b, Spring rose gall, Rhodites bicolor Harr.; c, goldenrod ball gall, Eurosto solidaginis Fitch; d, Dryophanta galls, Dryophanta lanata Gill; e mine of Phyllocnistis populiiella Cham. HOW TO COLLECT IMMATURE INSECTS 1. Sweeping. — There are usually numerous nymphs and larvae that live or hide in grass, weeds, shrubs and trees. Sweep the net back and forth on those plants in order to get those insects into the net. This method of collecting can usually give large returns. The con- tents of the net should be examined often and the specimens remov- ed before they are damaged by this vigorous treatment. 2. Trapping. — Many insects are attracted to food, certain chemicals, or places of shelter. We can use cans or bottles sunk into the ground and baited with molasses, fruits or meat. Not only the nymphs or larvae can be trapped in this way, but the eggs may also be laid by the adults. 3. Digging. — Many subterranean insects can be collected by digging in the earth. You will be surprised at the large numbers of insects a square foot of soil may contain. 4. Hand Picking. — This is the simplest method to collect insects. As a matter of fact, we use it frequently. When we see the insects we can simply pick them up in our hands. However, some insects have nettled hairs or strong mouth parts which may hurt the hands, there- fore, it is advisable to use a pair of tweezers or forceps on some species. 5. Netting in Water. — For the aquatic insects, a water net can be used for scraping the bottom or passing through vegetation in water. Occasionally the aerial net is used in water, but it is quite poor economy. 21 HOW TO KNOW THE IMMATURE INSECTS 6. Sifting. — Rinse the aquatic plants or bottom mud in a sifter. Many insects can be collected on the screens of the sifter (See Fig. 41). Sub- terranean insects may be easily secured by running the ground litter or soil through a sifter. 7. Separating. — Field soils, debris and animal nests or discharges can be put in a separator with a light on the top for heating. Some sepa- rators employ a stream of water to remove the insects from the debris. A good number of unusual insects may be collected in the receptacle. Those insects are usually small and active, or they feign death when disturbed, and can not be collected readily by ordinary methods. If heat is being used as in the Berlese trap, great care should be taken that the material does not catch fire. Your specimens may not only he damaged in this way but you could also have no place to work the next morning. COLLECTING APPARATUS 1. Sweeping Net. — The sweeping net needs to be strong enough to stand rough beating and sweeping. For the bag, 6-ounce drill, heavy a b f fC^~^ « ' e3.6'x2 Fig. 39. Sweeping net: a, net handle with metal cylinder to hold the ring in place; b, ring; c, net handle with grooves; d, bag. muslin or light canvas is usually recommended. The handle with a length of three to four feet and a diameter about an inch is desirable. 22 HOW TO KNOW THE IMMATURE INSECTS Many prefer a shorter handle; a few strokes of a saw will take core of that. 2. Water Net. — The triangular dredge has some advantages over other types because no matter which side rests on the bottom one of the blades will cut into the ground when the in- strument is dragged. Fig. 40. A triangular dredge. This dredge has a net of fairly close mesh, sturdy fabric. It may be drawn behind a boat or the net may be rolled into a compact body and thrown out to some distance from the shore then drawn back by its long cord. In the absence of a dredge net, a garden rake can be used to good advantage. The debris at the bottom of the water course is dragged out on the bank and examined for the insects that are hiding within it. As the water runs out of the debris the insects try to get back to the body of water also. 3. Sifter. — Any container with a wire- mesh bottom will serve this purpose. The size of the meshes in the screen depends upon the size of the insects, but for gener- al purposes eight meshes to the inch will be found useful. Figure 41 shows a sift- ing box which is good for collecting soil insects. Several sieves with different sized meshes will help separate the insect catch. The process should not be rushed, but the water turned on gently or many of the specimens will be damaged. Fig. 41. Sifter: A, water; B, screen; C, funnel; D-F, screens, from coarse to fine; G, water exit. 23 HOW TO KNOW THE IMMATURE INSECTS 4. Separator. — This is also known as the Ber- lese funnel. It consists of a funnel over which a sieve is placed. The funnel leads into a recep- tacle which contains liquid preservative. Over the top of the funnel a light bulb is placed by which the heat and light drive the insects down until they fall into the receptacle. A rack or special container is often employed to support the funnel. Where a constant source of hot water or steam is available the funnel may be surrounded by a water jacket or coils of hollow tubing which greatly reduces the fire hazard. Fig. 42. Separator: A, container; B, light; C, funnel; D, screen; E, preservative. 5. Aspirator. — This is also known as a suction bottle. It is conven- Fig. 43. Aspirator. lent to collect small insects either from the sweeping net or from under stones, bark, etc. Its construction is illustrated in the figure 43. 6. Other Apparatus. — Different sizes of bottles and vials are needed for storing insect specimens. Tweezers, forceps, pocket knife, small shovel or spade, note book, labels, etc., are all important in collecting insects. It is preferable to have a collecting bag to store those tools for fieldwork. HOW TO PRESERVE SPECIMENS For facihtating permanent study and handling, the insects must be killed and carefully preserved to make good specimens. It is impor- 24 HOW TO KNOW THE IMMATURE INSECTS tant that the specimens be kept in as good condition as possible. The insect body should retain its correct shape and the colors should like- wise be kept as true to life as possible. No one method is entirely sat- isfactory to cover all these aspects. Immature insects are not ordinarily mounted on pins, but 70% to 80% alchohol or other special liquid preservatives are used. Occasion- ally the small-bodied specimens need to be mounted on slides for mic- roscopic study. Before the insect is placed in the preservative it should be killed by putting it into boiling water for one to five minutes. The length of time in boiUng water depends entirely upon the size of the specimen. It will be sufficient when the specimen become swollen up. This method of fixing is found even better than by injecting the pre- servative into the insect body. For exhibition purposes, the larvae are often inflated and kept in dry condition. However, that is not desirable for scientific study, for during the process of inflation, many I cuticular appendages could be damag- j ed and the body color is sometimes (h^^^^r~''i~^~y'Tfr^^^^^ changed. Inflating larvae is rather ^^""^"-^-■'—^-uKAz^^x^-^-'^'^^ simple; place the larva on a clean blot- ter or a piece of paper and press the body contents out by gently rolling a round pencil from just back of the head to the end of the abdomen. Insert the drawn end of the glass tubing into the anal opening of the larva and secure it in place with the clips. Blow gently Fig. 44. An infigted and into the glass tubing so that the larva mounted larva. . ,. . , , . ^ IS distended to its normal size but not distorted, and warm it gently in an oven until dry. A lamp can be used for heating and a chimney or a tin can can be used as an oven. For blowing air into the body, it is better to use a hand bellows. An expansion bulb js desirable to give an even flow of air. When the specimen is thoroughly dry, remove it from the glass tubing and mount it on a kitchen match by inserting the match stem into the anal open- ing and then mount the match stem on a pin (see Fig. 44). If the speci- men i.*? too loose on the match stem, glue may be added. Specimens must always be accompanied by labels in which briel information of date, locality and collector are recorded. For the liquid preserved specimens, the label should be written with India ink or black pencil and the label put in the preservative with the specimen. For the pinned specimens, the label should be pinned below the speci man. Peterson recommends the following preservatives: 1. X.A. mixture: Xylene 1 part. 95% ethyl alcohol 1 part. Good for caterpillars, coleopterous larvae and Tenthredinid larvae. 25 HOW TO KNOW THE IMMATURE INSECTS 2. X.A.A.D. mixture: Xylene 4 parts. Commercial refined isopropyl alcohol 6 parts. Glacial acetic acid 5 parts. Dioxan 4 parts. Good for lepidopterous larvae and coleopterous larvae. 3. K.A.A.D. mixture: Kerosene 1 part. 95% ethyl alcohol or refined commercial isopryl alcohol 7-9 parts. Glacial acetic acid 1 part. Dioxan 1 part. Good for maggots, lepidopterous larvae, hymenopterous larvae and pupae, coleopterous larvae and neuropterous larvae. But it does not produce satisfactory specimens where larvae possess a thick exo skeleton, namely wireworms and similar species or among some aqua- tic insects especially immature stages of Zygoptera and Ephemeroptera. Larvae collected in the field are dropped into the killing solution and kept submerged until they are completely distended. If narrow vials are used for large larvae they should be places in a horizontal position until the larvae straighten out and become firmly set. This may take from one to several hours depending upon the species. At the end of this period the larvae should be transferred to ethyl alcohol. Larvae possessing a firm exoskeleton may be preserved in 75 7o ethyl alcohol, while soft bodied forms killed in K.A.A.D. mixture should be preserved in 95% ethyl alcohol to prevent any collapse. HOW TO REAR IMMATURE INSECTS For studying the life history or identifying the adult stage, the im- mature insects are often reared in the laboratory. Rearing insects is quite a technical job. The natural conditions under which the imma- ture insects were found should be simulated as closely as possible. The following is just a brief account of the more important aspects. 1. Cage. — Screen cages of different sizes are desirable for rearing immature insects. The food plant can be cultured in soil or in water and put in the cage. For rearing a large number of isolated individual insects it is usually difficult to provide a large number of cages and bottles or vials are used instead. 2. Food. — The kind of food material the insect feeds on must be de- termined at the start. Ordinarily the rearing container is not large enough for putting the entire food material inside, so fresh food should be suppLed every day. For example, leaves or the other parts of plants should be provided for the phytophagous insects and they al- ways should be kept fresh. Insects that infest seeds and those that 26 HOW TO KNOW THE IMMATURE INSECTS cause plant galls may be reared by enclosing the seeds or galls in a tight container. Parasitic wasps may be reared from their hosts by keeping the host until the adult parasites emerge. Boring insects can be left in the original food material and kept in a cage until they emerge. 3. Humidity. — Humidity plays an important part in rearing insects. If the condition inside of the container is too dry the food material becomes unsuitable for the insects. On the other hand, if the humidity is too high, moisture will be deposited on the sides of the container and frequently the death of the insect will result. To adjust the humid- ity of a vial or a bottle, changing of the materials of the stopper is sometimes found practicable. A cork stopper can keep the humidity much higher than a stopper of cotton. Insects that feed on decaying animal matter should have the cage provided with slightly moist soil or sand. 4. Pupation. — Insects that are being reared often die during the pupal stage. This requires a careful study of the pupation habits. Some in- sects make silk or soil cocoons and some just pupate in the soil with- out forming any covering. Soil must be added to the cage to meet the needs of the insect, otherwise a successful fearing will not be ob- tained. The cocoon should not be removed artificially from its enclos- ed pupa for it is necessary to protect the insect. The over-wintering pupae should be kept in good condition. Cold can kill the pupae and too high temperatures may cause the pupae to emerge too early. 5. Preserve the different stages. — For life history study, no\ only the different stages and different instars need to be preserved, but also the cast larval skins, pupal cases and cocoons which are very im- portant in scientific study. These should all be carefully labeled. 6. Recording. — Every change of the insect, both morphological and physiological, should be recorded at once. The student may devise his own form of records but should keep them uniform and with all the necessary details. Careless observations and records are worse than none at all; the latter can not be misinterpreted. 27 HOW TO KNOW THE IMMATURE INSECTS The following form is recommendated for recording the life history: MONTH YEA^,/f-<^. 1N5EC1 / O S__ -■ — ^ / 2 3 ■* S c 7 S 9 /. '/ '^ 13 '♦ '3- '.« '7 /» 'f ^» 2' ZZ '^ e-i if Z( iy Zi it 3o / t f c e f e s f n H M M n w H M H M, 1^ M, M, '< M, g «, M- '•'r ". *s "l -77 "l «. '♦l «. M «, P r r r /» P r -f^ A A A A A J A i> A 3/ 1 Kfc»