1496. KEY TO THE FAMILIES OF NORTH AMERICAN INSECTS AN INTRODUCTION TO THE CLASSIFICATION OF INSECTS BY CHARLES T. BRUES Assistant Professor of Economic Entomology Harvard University AND A. L. MELANDER Professor of Entomology, State College of Washington BOSTON, MASS., AND PULLMAN, WASH. Published by the Authors 1915 Copyright, 1915 Charles T. Brues, and A. L. Melander Published March, 1915 THE RUMFORD PRESS CONCORD, N. H. U.S.A. TO OUR FORMER TEACHERS, HERBERT EUGENE WALTER, OLIVER S. WESTCOTT, AND WILLIAM MORTON WHEELER, THIS BOOK IS DEDICATED. 2051559 PREFACE. The present manual attempts to bring together a brief yet com- plete key to the families of American insects, unhampered by more than the explanations needed to make such a tabulation available to the general student. It has been prepared to meet the require- ments, not alone of college courses in systematic entomology, but also of agricultural high schools and of physicians, fruit inspectors, the modern farmer, the nature-lover, or any one who is concerned with the practical identification of insects. More than fifty thousand different species of insects are now known from North America. Their descriptions fill libraries and their final identification requires the knowledge of specialists. Obviously no single volume can provide for their determination. But this host of species is divided into groups of related forms, the families of insects, and it is with their recognition that the present work deals. Identification of the families has been effected by means of analytical keys, which have been arranged as dichotomies. In the first couplet, for example, two contrasting descriptions are given, one of which should agree with the insect to be determined. The number at the end of this description indicates the couplet which should then be studied, and so on until the final name is secured. All of the keys have been arranged in this way, as the writers' experience in the classroom shows that specimens can be most easily and rapidly classified with a key of this type, which also requires much less space for printing. While the dichotomies frequently represent the natural relationships or the lines of phyletic development, no attempt has been made to preserve natural divisions wherever the convenience and practical opera- tion of the keys would have been sacrificed. As the tabulation is designed mainly for identification, charac- ters not readily seen on the usual pinned laboratory specimens have been minimized. The nomenclature of the body-parts and of the wings has been adapted from that used in the bulk of the systematic literature upon the separate orders. Such terms un- fortunately do not always agree with undoubted homologies of these parts but are those which are encountered in the literature to which reference must be made for more extended taxonomic vi Preface. work. A special glossary and drawings of anatomical details will familiarize the student with unusual terms. The keys are intended only for adult insects as there is as yet no complete guide to the younger stages, although a few hints are given in the key to or- ders to indicate the position of immature forms. For a bibliography of the more important papers dealing with the further classification of North American insects, the student is referred to Banks, Bulletin No. 81, Bureau of Entomology, U. S. Department of Agriculture (1910). Preceding each family name are cited several representative genera, and, in the case of a number of economically important species, the common and specific names are also given, inclosed in brackets after the generic name. Thus the genera are in heavy- face type, the Latin specific names in italics, and the common names in Roman. A few synonyms have been inserted, in italics,, both for genera and for families, to associate the names here used with others commonly occurring in publications. The family names have been formed in accordance with the rule of the zoo- logical code requiring the suffix -idee after the root of the oldest genus name, although this has resulted in a number of minor changes in orthography. The pronunciation of the Latin names is indicated by an accent mark, placed over the vowel in the ac- cented syllable, a long vowel indicated by a grave accent (e.g. e) and a short one by an acute accent (e.g. 6). The Linnean classification of insects into seven orders has been long abandoned as an artificial grouping of unrelated forms. We have followed the unified ordinal groups essentially as limited by Handlirsch.1 The families of a few of the orders recently monographed have been adopted almost without change. Thus the Dermaptera are based on Burr,2 the Hemiptera on Reuter,3 the Lepidoptera to a great extent on Forbes,4 the Mallophaga on Kellogg,5 the Strepsip- tera on Pierce,6 and the Trichoptera on Ulmer.7 ' Die foesilen Inaekten und die Phylogenie der rezenten Fonnen. Leipzig, 1908. Wilhelm Englemann. » Wytsman's Genera Insectorum, fasc. 122 (1913). »Oefv. Fin. Vet. Forh., liv, (1911-12). « Psyche, xxi, 53-65 (1914). 'Wytsman's Genera Insectorum, fasc. 66 (1908). •Bull. U. S..Nat. MUB., No. 66 (1909). 7 Wytsman's Genera Insectorum, fasc. 60 (1907). Preface. vii The families of the Coleoptera are mainly those recognized by Sharp and Ganglbaur, and largely reverse the familiar sequence given by Le Conte and Horn. Two or three orders do not occur in North America, but have been added to the key for the sake of completeness. A few families absent in North America have representatives in Central America or the West Indies, and these also have been included. The present system of insect classification has gradually been evolved by many workers in almost innumerable contributions published during the course of more than a century. During this time systems have been proposed, wholly or partially discarded, or incorporated into new ones. The task of the writers has been little more than to compile from this existing literature the most recent ideas, and they have gleaned from so many sources in various languages that it is impossible to refer to all in detail. To some extent this is also true of the illustrations which have been verv largely redrawn from published figures, by Beirne Barrett Brues, the wife of one of the authors. The original source of the drawings is indicated on the explanations to the plates by the name of the author in parentheses, although it must be stated that many have been simplified, differently lettered, or otherwise modified to adapt them to the purpose of the present manual. While family groupings should be of equal rank throughout the animal kingdom, they are not always coordinate, since they are concepts rather than concrete divisions and hence are subject to the variability of ideas. That the specialist is apt to narrow his limi- tations can be seen by the constantly increasing number of families proposed. For example, the old group Tachinidae, geologically one of the most recent of insects, has been segregated into scores of so-called families. If this course is accepted in one group it carries with it a tacit elevation of all other ranking minor groupings and thus the family concept becomes altered. Since views on classification irresistibly shift through such changes and are con- stantly diverted by the discovery of annectant forms, no taxo- nomic scheme can be considered complete or final. While the writers have to some extent attempted to keep the family groupings balanced, yet they fully appreciate the futility of such an endeavor and present the following outline as seemingly that most widely accepted by present-day entomologists. CONSPECTUS OF THE HIGHER GROUPS OF INSECTS. Class PTERYGOGENEA Subclass Orthopteroidea Order GRYLLOBLATTOIDEA (Grylloblattidse) Order ORTHOPTERA Suborder Acridoidea (Acridiidae, Tettigidae) Suborder Locustoidea (Locustidae, Gryllidse, Gryllotalpidae, Tridactylidae) Order PHASMOIDEA (Phasmidae) Order DIPLOGLOSSATA (Hemimeridae) Order DERMAPTERA (Pygidicranidae, Labiduridse, Labiidae, Forficulidse) Order THYSANOPTERA Suborder Terebrantia (^Eolothripidas, Thripidae) Suborder Tubulifera (Phloeothripidse) Subclass Blattaeformia Order MANTOIDEA (Mantidae) Order BLATTOIDEA (Blattidae) Order ZORAPTERA (Zorotypida:) Order ISOPTERA (Protermitidas, Termitidae) Order CORRODENTIA (Psocidae, Atropidae) Order MALLOPHAGA Suborder Ischnocera (Trichodectidae, Philopteridae) Suborder Amblycera (Gyropodidae, Liotheidae) Order SIPHUNCULATA (Pediculidae, Haematopinidae, Echinophthiriidae) Subclass Hymenopteroidea Order HYMENOPTERA Suborder Chalastogastra (Xyelidae, Pamphiliidae, Oryssidae, Cephidae, Xiphydriidae, Siricidae, Cimbicidae, Hylotomidae, Diprionidae, Ten- thredinidae, Pterygophoridae) Suborder Clistogastra ICHNEUMONIFORMIA : ICHNEUMONOIDEA (Evaniidae, Roproniidae, Stephanidae, Alysiidae, Ichneumonidae, Capitoniidae, Braconidae, Myersiidae) CYNIPOIDEA (Figitidaa, Ibaliidae, Cynipida?) CHALCIDOIDEA (.Mymaridae, Agaonidae, Eucharidae, Perilampidae, Callimomidae, Leucospidae, Chalcididae, Eurytomidae, Cleonymidae, Miscogastridse, Pteromalidae, Eulophidae, Elasmidae, Trichogrammat- ida3) VESPIFORMIA (Trigonaloidaa, Heloridae, Diapriidae, Platygastridae, Scelionidae, Ceraphronidae, Formicidae, Vanhorniidae, Chrysididae, 2 1 Key to Families of North American Insects. Bethylidse, Embolemidae, Dryinidse, Serphidae, Pelecinidae, Vespidae, Eumenidae, Psammocharidae, Masaridse, Sapygidae, Myzinidae, Tiphiidae, Scoliidse, Rhopalosomatidae, Myrmosidae, Cosilidae, Mutillidse SPHECIFORMIA (Crabronida?, Oxybelidas, Trypoxylonidae, Philan- thidae, Bembecidae, Nitelidae, Larridae, Psenidae, Mellinidae, Ampu- licidae, Sphecidae, Stizidae, Nyssonidae, Alysonidae, Gorytidaa) ANTHOPHILA (Apidaa, Bombidse, Prosopidae, Colletida?, Andrenidae, Panurgidae, Anthophoridae, Nomadidae, Melectidse, Megachilidas, Xylocopidae, Ceratinidae) Subclass Coleopteroidea Order COLEOPTERA Suborder Adephaga (Cicindelidas, Carabidaa, Haliplidae, Amphizoidae, Dytiscidae, Gyrinidae, Rhysodidae, Cupedidae) Suborder Polyphaga PALPICORNIA (Hydrophilidae) STAPHYLINIFORMIA (Silphidse, Scydmamidse, Leptinidae, Clam- bidae, Aphenocephalidae, Orthoperidae, Ptiliidae, Sphaariidae, Hydro- scaphidae, Scaphidiidae, Pktypsyllidae, Staphylinidae, Pselaphidae, Histeridaa) MALACODERMATA (Lampyrida?, Lycidae, Telephoridae, Malachiidae, Cleridae, Corynetidae, Derodontidae) CUCUJOIDEA (Cucujidas) CLAVICORNIA (Synteliidae, Ostomatidae, Nitidulidae, Erotylida3, Cryptophagidae, Phalacridae, Lathridiidae, Mycetophagidae, Adi- meridae, Colydiidae, Cioidae, Sphindidae, Endomychidae, Coccinellidae) BRACHYMERA (Byturidae, Dermestidaa, Nosodendridae, Byrrhidae) MACRODACTYLIA (Georyssidae, Heterocerida?, Helodidss, Eucin- etidae, Dryopidae) SERRICORNIA (Chelonariidae, Dascillidae, Rhipiceridae) STERNOXIA (Cebrionidae, Ekteridse, Eucnemidaa, Throscida;) BUPRESTOIDEA (Buprestidae) TEREDILIA (Lymexylonidae, Micromalthidae, Bostrichidae, Lyctidae, Ptinidae, Anobiidae) HETEROMERA (CEdomeridae, Cephaloonidae, Pythidae, Pyrochroidae, Hylophilidae, Pedilidae, Anthicidaa, Melandryidae, Scraptidae, Mon- ommidae, Othniidae, ^Egialitidae, Lagriidae, Cistelidae, Tenebrionidas, Meloidae, Mordellidae, Rhipiphoridae) PHYTOPHAGA (Cerambycida?, Chrysomelidae, Bruchida2) RHYNCHOPHORA (Platj-podidte, Ipidae, Curculionidas, Anthribidse, Brenthidre) LAMELLICORNIA (Lucanidaa, Sinodendridae, Passalida?, Trogidae, Scarabseidae) Order STREPSIPTERA (Mengeidae, Xenidae, Halictophagida?, Elenchidaa) Conspectus of the Higher Groups of Insects. 3 Subclass Embidaria Order EMBDDINA (Olynthidre, Oligotomidae, Embiidse) Subclass Libelluloidea Order ODONATA Suborder Zygoptera (Calopterygidae, Agrionidae) Suborder Anisoptera (JSschnida?, Libellulidae) Subclass Ephemeroidea Order PLECTOPTERA (Ephemeridffi) Subclass Perloidea Order PLECOPTERA (Perlidse) Subclass Neuropteroidea Order MEGALOPTERA (Sialididse, Corydalidae) Order RAPHIDIOIDEA (Raphidiidse) Order NEUROPTERA (Mantispida?, Ascalaphidae, Myrmeleonidae, Chrysop- idae, Dilaridae, Polystoechotida?, Berothidae, Sysyridse, Hemerobiidas, Coniopterygidas) Subclass Panorpoidea Order PANORPAT^E (Panorpidae, Bittacusidae, Meropida;, Boreidae) Order TRICHOPTERA (Hydroptilidae, Philopotamida?, LimnephDidae, Rhy- acophilida?, Phryganeidae, Polycentropidae, Hydropsychidae, Psychomyiidae, Calamocerotida?, Sericostomatidae, Molannidae, Leptoceridae, Odonto- cerida3) Order LEPIDOPTERA Suborder Jugatae (Hepialidae, Micropterygidae) Suborder Frenatae TINEOIDEA: (Adelidae, Gracilariida;, Lyonetiidae, Tischeriidae, Acro- lepiidas, Prodoxidae, Opostegidae, Nepticulidae, Tineidae, Heliozelidae, Heliodinidae, Cosmopterygida?, Elachistidae, Blastobasida?, Ethmiidae, (Ecophoridae, Stenomidae, Gelechiidae, Yponomeutida?, Tortricidae, Pterophoridse, Orneodidae, Pyralididae, ^Egeriidae, Castniidae, Cossidae, Thyrididae, Chalcosiidae, Pyromorphidae, Dalceridae, Megalopygidae, Eucleidae, Psychidae, Lacosomatidae, Nolidae) BOMBYCOIDEA: (Uraniidae, Epiplemidae, Geometridaa, Drepanidae, Bombycidae, Lasiocampidae, Liparidae, Thyatiridae, Eupterotidae, Notodontidae, Dioptidae, Pericopidae, Noctuidae, Agaristidae, Arctiidae, Lithosiidae, Hypsidae, Syntomidae) SATURNOIDEA: (Saturniidas, Ceratocampidse) SPHINGOIDEA: (Sphingidaj) PAPILIONOIDEA: (Hesperiidae, Lycaenidae, Erycinidae, Libytheidse, Lymnadidae, Ithomiida?, Heliconiidae, Brassolidae, Agapetidae, Morpho- idae, Nymphalidae, Pieridae, Papilionidae, Parnassiidae.) Key to Families of North American Insects. Order DIPTERA Suborder Orthorrhapha NEMATOCERA TIPULOIDEA: (Dixidae, Tipulidse, Limnobiidse, Ptychopteridse, Psy- chodidae, Culicidae, Chironomidae, Sciaridae, Cecidomyiidse, Scatopsidae, Mycetophilidae. BIBIONOIDEA: (Rhyphidae, Orphnephilidae, Blepharoceridae, Bibionidae, Simuliidae) BRACHYCERA EREMOCILETA: (Stratiomyiidae, Pantophthalmidae, Xylophagidse, Ccenomyiidae, Tabanida?, Rhagionidas) TROMOPTERA: (Cyrtidse, Nemestrinidas, Apioceridas, There vidae, Bombyliidse, Scenopinidas) DERMATINA: (Mydaidse) ENERGOPODA: (AsiUdae) ORTHOGENYA: (Empididae, DolichoPodida2) ACROPTERA: (Lonchopterid«) HYPOCERA: (Phoridae) Suborder Cyclorrhapha ASCHIZA: (Platypezidas, Pipunculidae, Syrphidas, Conopidas,) SCHIZOPHORA: MYODARIA SCHIZOMETOPA: (Gastrophilidae, CEstridae, Phasiidas, Megapro- sopidse, Calliphoridae, Sarcophagidas, Rhinophoridae, Dexiidae Tachinidae, Muscidae, Anthomyiidae) HOLOMETOPA: (Helomyzidaa, Scatophagidas, Heteroneuridie, Phy- codromida», Borboridas, Sepsidae, Tanypezidaa, Micropezidae, Rhopalomeridae, Dryomyzidae, Tetanoceridae, Lauxaniidae, Orta- lididse, Lonchaeidae, Trypetidae, Ephydridae, Milichiidse, Droso- philidae, Chloropidae, Geomyzidae, Piophilidae, Agromyzidae, Och- thiphilidae, Psilidae, Diopsidae) PUPIPARA: (Nycteribiidae, Streblidaa, Hippoboscidae) Order SUCTORIA. (Pulicidae, Ctenopsyllidae, Hystrichopsyllidae, Cerato- psyllidse, Rhynchoprionidse) Subclass Rhynchota Order HOMOPTERA Suborder Auchenorrhyncha (Cicadidae, Membracidas, Cercopidae, Bytho- scopidae, Proconiidae, Jassidae, Typhlocybidae, Fulgoridae, Cixiidas, Ach- ilidae, Derbidae, Issidae, Flatidae, Delphacidae) Suborder Psylloidea (Psyllidae) Suborder Aleurodoidea (Aleurodidae) Suborder Aphidoidea (Aphidida?) Suborder Coccoidea (Coccidae) Order HEMIPTERA (Ochteridas, Nerthridae, Naucoridae, Belostomatidae, Nepidae, Notonectidae, Corixidae, Dipsocoridae, Schizopteridaa, Cimicidae, Miridae, Isometopidae, Anthocoridae, Gerridae, Veliidae, Hydrometridae, Conspectus of the Higher Groups of Insects. 5 Polyctenidae, Aradidae, Dysodiidae, Nabidae, Henicocephalidae, Mesoveliidse, Acanthiidse, Macrocephalidse, Reduviidse, Emesidae, Hebridae, Pyrrhocor- idae, Tingitidae, Corizidse, Coreidae, Alydida?, Piesmidae, Myodochidae, Neid- idss, Pentatomidae, Thyreocoridae, Scutelleridse. Class THYSANURA Order LEPISMATOIDEA (Lepismatida?) Order MACHILOIDEA (Machilidffi) Class CAMPODEOIDEA Order RHABDURA (Projapygidae, Campodeidse) Order DICELLURA (Japygidse) Class COLLEMBOLA Order ARTHROPLEONA (Aphoruridae, Entomobryidse, Poduridse) Order SYMPHYPLEONA (Sminthuridae, Papiriidae, Neelidaa) Class MIRIENTOMATA Order PROTURA (Eosentomidse) KEY TO THE ORDERS OF INSECTS. 1. Wings developed 2 Wingless, or with vestigial wings 29 2. The wings of the mesothorax (the fore wings) horny, leathery or parchment- like; prothorax large and separate from the mesothorax (except in the rare Strepsiptera, which have minute fore wings) 3 The mesothoracic wings membranous 11 3. Mesothoracic wings (called tegmina or hemelytra) containing veins, or at least the metathoracic wings not folded crossways when hidden under the upper wings 4 Mesothoracic wings (called elytra) veinless, of uniform consistency, the meta- thoracic wings, when present, folded crossways as well as lengthwise when at rest and hidden beneath the elytra; mouth mandibulate 10 4. Mesothoracic wings of uniform texture, usually with many veins; head verti- cal 5 Mesothoracic wings leathery at the base, membranous at the tip, usually over- lapping the abdomen when at rest; head usually horizontal; mouth beak- like or awl-shaped, fitted for sucking. True Bugs. .HEMIPTERA (Page 76) 5. Mouth with the mandibles fitted for chewing 6 Mouth fitted for sucking, the beak arising from the back part of the head and projecting backward HOMOPTERA (Page 73) 6. Hind wings not folded, similar to the fore wings; social species, living in colonies. Termites ISOPTERA (Page 17) Hind wings folding, broader than the fore wings 7 7. Usually rather large or moderately large species; antennae lengthened and thread-like; prothorax large and free from the mesothorax; cerci present; fore wings rarely minute, usually long 8 Very small active species; antennae short, with few joints; no cerci; fore wings minute; prothorax small. Rare, short-lived insects, parasites of other insects, usually wasps and bees. Males of STREPSIPTERA (Page 41) 8. Hind femora not larger than the fore femora; mute species; body more or less flattened with the wings superposed when at rest; tergites and sternites subequal 9 Hind femora almost always much larger than the fore femora, jumping species, if not (Gryllotalpa) the front legs broadened for burrowing; species capable of chirping or making a creaking noise; body more or less cylindrical, the wings held sloping against the sides of the body when at rest; tergites usually larger than the sternites. Grasshoppers, Katydids, Crickets ORTHOPTERA (Page 13) 9. Body elongate; head transverse, vertical, free, not set into the very long prothorax; front legs spined, formed for grasping prey; deliberate movers. Mantis MANTODDEA (Page 16) Body oval, much flattened; head nearly concealed underneath the oval prono- tum; legs similar and fitted for rapid running, the coxa? large. Roaches BLATTOIDEA (Page 16) 6 Key to the Orders of Insects. 7 10. Abdomen terminated by movable forceps; antennae long and slender; fore wings short, hind wings nearly circular, delicate, radially folded from near the center; elongate insects. Earwigs DERMAPTERA (Page 15) Abdomen not terminated by forceps; antennae of various forms but usually eleven-jointed; fore wings usually sheathing the abdomen; generally hard- bodied species. Beetles . : COLEOPTERA (Page 30) 11. With four wings 12 With but two wings (the mesothoracic) usually outspread when at rest 27 12. Wings long, very narrow, the margins fringed with long hairs, almost veinless; tarsi one- or two-jointed, with swollen tip; mouth without biting mandibles, fitted for sucking; no cerci; minute species. Thrips THYSANOPTERA (Page 15) Wings broader and most often supplied with veins, if rarely somewhat linear the tarsi have more than two joints and the last tarsal joint is not swollen, 13 13. Hind wings with the anal area folded in plaits, fan-like, in repose, larger than the fore wings; antennae prominent; veins usually numerous; larvae aquatic, 14 Hind wings not folded, not larger than the fore wings, the anal area small and not separated 16 14. Tarsi five-jointed; cerci not pronounced . . . 15 Tarsi three- jointed; body rather flattened, with jointed cerci; wings at rest over- lapping the abdomen; species of moderate to large size. Stone-flies PLECOPTERA (Page 44) 15. Costal area with few crossveins; wings with the surface hairy; prothorax small; species of small to moderate size. Caddice-flies TRICHOPTERA (Page 46) Costal area with many crossveins; prothorax rather large; species of moderate to large size MEGALOPTERA (Page 44) 16. Antennae short and inconspicuous; wings netveined with numerous crossveins; larvae aquatic. (SUBULICC-RNIA) 17 Antennae larger, distinct, if rarely small the crossveins are few; larvae terres- trial 18 17. Hind wings much smaller than the fore wings; abdomen ending in long, thread- like processes; sluggish fliers. May-flies PLECTOPTERA (Page 43) Hind wings nearly like the fore wings; no caudal setae; vigorous, active fliers, often of large size. Dragon-flies, Damsel-flies ODONATA (Page 43) 18. Head produced into a mandibulate beak; hind wings not folded; wings usually with color pattern, the crossveins numerous; male genitalia forming a swollen pincers-like termination of the abdomen. Scorpion-flies PANORPAT^; (Page 46) Head not drawn out as a beak; male abdomen not forcipate 19 19. Mouth mandibulate 20 Mouth haustellate, the mandibles not formed for chewing; no cerci; crossveins few 25 20. Tarsi five-jointed; no cerci 21 Tarsi two-, three- or four-jointed; veins and crossveins not numerous 23 8 Key to Families of North American Insects. 21. Prothorax small or only moderately long 22 Prothorax very long and cylindrical; antennae many-jointed; crossveins nu- merous RAPHZDIOIDEA (Pagt 44) 22. Wings similar, with many veins and crossveins, costal cell almost always filled with crossveins; prothorax more or less free. If the neuration is very rarely reduced (Coniopteryx) the wings are powdered. .NEUROPTERA (Page 45) Wings with relatively few angular cells, the costal cell without crossveins; hind wings smaller than the fore pair; prothorax fused with the mesothorax; abdomen usually constricted at the base and ending in a sting or specialized ovipositor. Wasps, Bees, etc HYMENOPTERA (Page 19) 23. Prothorax well developed; wings equal in size, held superimposed on the abdo- men when at rest 24 Prothorax inconspicuous; hind wings smaller than the fore wings; tarsi two- or three-jointed; wings at rest held roof-like against the abdomen CORRODENTIA (Page 17) 24. Tarsi apparently four-jointed; social species, living in colonies ISOPTERA (Page 17) Tarsi three-jointed, the front metatarsi swollen; solitary; southern species EMBHDINA (Page 42) 25. Wings not covered with scales, usually transparent, not outspread when at rest; prothorax large; antennae with few joints 26 Wings and body covered with scales, the wings well developed and pictured; prothorax small; antennas many-jointed. Moths and Butterflies LEPIDOPTERA (Page 48) 26. Beak arising from the back of the head HOMOPTERA (Page 73) Beak arising from the front part of the head HEMIPTERA (Page 76) 27. Mouth not functional; abdomen furnished with a pair of caudal filaments. .28 Mouth-parts forming a proboscis, only exceptionally vestigial; abdomen with- out caudal filaments; hind wings replaced by knobbed halteres. Flies, Mosquitoes, Midges DIPTERA (Page 61) 28. No halteres; antennae inconspicuous; crossveins abundant. A few rare May- flies PLECTOPTERA (Page 43) Hind wings represented by minute hook-like halteres; antennas evident; cross- veins lacking. Males of Scale-insects HOMOPTERA (Page 73) 29. Body more or less insect-like, i. e. with more or less distinct head, thorax and abdomen, and jointed legs, and capable of locomotion 30 Without distinct body parts, or without jointed legs, or incapable of locomo- tion 70 30. Terrestrial, breathing through spiracles 31 Living in the water; usually gill-breathing, larval forms 59 Parasites on warm-blooded animals 65 31. Mouthparts vestigial, retracted in the head and scarcely or not at all visible; underside of the abdomen with styles or other appendages; very delicate small or minute insects 32 Mouthparts mandibulate, formed for chewing 38 Mouthparts haustellate, formed for sucking 55 Key to the Orders of Insects. 9 32. Abdomen consisting of ten or eleven segments, no ventral sucker at its base, no- terminal springing apparatus 33 Abdomen consisting of six segments or less, with a forked sucker on the first ventral segment and usually with a springing apparatus (furcula) near the tip beneath. (Class COLLEMBOLA) 37 33. Basal three segments of the abdomen with ventral styles; antennae absent; no cerci but a short anal tube present; head pear-shaped; prothorax short. (Class MIRIENT6MATA) PROTURA (Page 83) Ventral styles occurring to the seventh segment; antennae thread-like; cerci present; prothorax not short 34? 34. Body never scaly; mouthparts concealed except for the palpi; apex of the ab- domen without a median process. (Class CAMPODEOIDEA) 35 Body usually covered with minute scales; tips of the mouthparts visible; abdo- men with a median cerciform appendage. (Class THYSANtlRA) 36 35. Eleventh tergite nearly or quite covered by the tenth; cerci jointed; anal valves very distinct RHABDURA (Page 82) Eleventh tergite fused with the tenth; cerci single-jointed forming strong forceps; anal valves not distinct DICELLURA (Page 82) 36. Body flattened; eyes not extending over the front; maxillary palpi five- or six- jointed; eleventh tergite partly covered by the tenth LEPISMATOIDEA (Page 81) Body convex above; eyes large, extending over the front; maxillary palpi seven- jointed; eleventh tergite not covered by the tenth MACHILOiDEA (Page 81) 37. Abdomen comprising six evident segments; body lengthened, subcylindrical ;. fourth segment of the abdomen often much lengthened ARTHROPLEONA (Page 82) Abdominal segments in part fused; body subglobular, the abdomen little longer than wide SYMPHYPLEONA (Page 83) 38. Underside of abdomen entirely without legs 30 Abdomen bearing false legs beneath which differ from those of the thorax; body cylindrical, the thorax and abdomen not distinctly separated; larval forms. 54 39. Antennae long and distinct '. 40 Antennae short, not pronounced; larval forms 52 40. Abdomen terminated by strong movable forceps; prothorax free. Earwigs DERMAPTERA (Page 15) Abdomen not ending in forceps 41 41. Abdomen not strongly constricted at the base, broadly joined to the thorax, 42 Abdomen strongly constricted at the base; prothorax fused with the meso- thorax. Ants, etc HYMENOPTERA (Page 19} 42. Head not prolonged into a beak 43- Head produced into a mandibulate beak; species found about snow. (Boreus) PANORPAT^I (Page 46) 10 Key to Families of North American Insects. 43. Very small (three millimeters) louse-like jumping species; prothorax incon- spicuous. Book-lice CORRODENTIA (Page 17) Larger, or at least not louse-like species; prothorax large 44 44. Hind legs fitted for jumping, the femora enlarged; wing-pads of larva? when present in inverse position, the metathoracic overlapping the mesothoracic ORTHOPTERA (Page 13) Hind legs not enlarged for jumping; wing-pads, if present, in normal posi- tion 45 45. Prothorax much longer than the mesothorax; front legs fitted for grasping prey MANTOIDEA (Page 16) Prothorax not greatly lengthened 46 46. Cerci present; antennae usually with more than fifteen joints, often many- jointed 47 No cerci; body often hard-shelled; antennas usually with eleven joints COLEOPTERA (Page 30) 47. Cerci with more than three joints 48 Cerci short, with one to three joints 49 48. Body flattened and oval; head inflexed; prothorax oval. Roaches. BLATTOIDEA (Page 16) Body elongate; head nearly horizontal; prothorax quadrate. GRYLLOBLATTOIDEA (Page 13) 49. Tarsi five-jointed; body very slender and long. Walking-sticks PHASMOIDEA (Page 14) Tarsi two- to four-jointed; body not linear 50 50. Front tarsi not enlarged 51 Front tarsi with the first joint swollen EMBKDINA (Page 42) •51. Tarsi apparently four-jointed; cerci with several joints; antennae with nine to thirty joints ISOPTERA (Page 17) Tarsi two-jointed; cerci one-jointed; antennae nine-jointed; minute species restricted to the East Indies ZORAPTERA (Page 17) 52. Body cylindrical, caterpillar-like PANORPATAE (Page 46) Body more or less depressed, not caterpillar-like 53 53. Mandibles united with the corresponding maxillae to form sucking jaws Larvae of Neuroptera Mandibles almost always separate from the maxillae Larvae of Cole6ptera, Raphidioidea, Strepsiptera 54. False legs numbering five pairs or less Larvae of Lepidoptera False legs numbering six to eight pairs Most larvae of suborder Chalastogastra, Hymenoptera 55. Body bare or with few scattered hairs 56 Body densely clothed with hairs or scales; proboscis if present coiled under the head. Moths LEPIDOPTERA (Page 48) 56. Last tarsal joint swollen and with no claws; mouth consisting of a triangular unjointed beak; minute species. Thrips .... THYSANOPTERA (Page 15) Tarsi not bladder-like at the tip, and with distinct claws 57 Key to the Orders of Insects. 1 1 •57. Prothorax distinct 58 Prothorax small, hidden when viewed from above DIPTERA (Page 61) 58. Beak arising from the front part of the head. . . .HEMIPTERA (Page 76) Beak arising from the back part of the head. . . .HOMOPTERA (Page 73) 59. Mouth mandibulate 60 Mouth haustellate, forming a strong pointed inflexed beak Nymphs of Hemiptera 60. Body not encased in a shell made of sand, pebbles, leaves, etc 61 Case-bearing forms. Periwinkles Larvae of Trichoptera 61. Abdomen furnished with external lateral gills or respiratory processes (a few Coleoptera here also) 62 Abdomen without external gills 63 62. Abdomen terminated by two or three long feathery gill-processes Larvae of Plectoptera Abdomen with short end-processes Larvae of Megal6ptera 63. Lower lip strong, extensile, and furnished with a pair of opposable hooks Larvae of Odonata Lower lip not capable of being thrust forward and not hooked 64 64. The three divisions of the thorax loosely united; antennae and caudal filaments long and slender Larvae of Plecoptera Thoracic divisions not constricted; antennae and caudal filaments short Larvae of Coleoptera 65. Body flattened 66 Body strongly compressed; mouth formed as a sharp inflexed beak; jumping species. Fleas SUCTORIA (Page 72) 66. Mouthparts formed for biting (chewing) 67 Mouthparts formed for piercing and sucking 68 67. Mouth inferior; cerci long; African species parasitic on rodents DIPLOGLOSSATA (Page 14) Mouth anterior; no cerci; generally elongate-oval insects with somewhat tri- angular head; parasites of birds or mammals. Biting-lice MALLOPHAGA (Page 18) 68. Antennae exserted, visible, though rather short 69 Antennae inserted in pits, not visible from above Pupiparous DIPTERA (Page 61) 69. Beak unjointed; tarsi formed as a hook for grasping the hairs of the host; per- manent parasites. Lice SIPHUNCULATA (Page 18) Beak jointed; tarsi not hooked; temporary parasites HEMIPTERA (Page 76) 70. Legless, grubs, maggots or borers; locomotion effected by a squirming motion. Larvae of some beetles, flies, moths, ants, bees and wasps. If living in the body of wasps or bees, with the head exposed, compare the females of Strepsiptera. Sedentary forms, incapable of locomotion 71 12 Key to Families of North American Insects. 71. Small degraded forms bearing little superficial resemblance to insects, with a long slender beak, and usually covered with a waxy scale or powder or cot- tony tufts; living on various plants. Scale insects HOMOPTERA (Page 73) Body quiescent, but able to bend from side to side; not capable of feeding, enclosed in a skin which is tightly drawn over all the members, or which leaves the limbs free but folded against the body; sometimes free, sometimes enclosed in a cocoon or in a shell formed from the dried larval skin 72 72. The skin encasing the legs, wings, etc., holding the members tightly against the body; prothorax small; a proboscis showing 73 Legs, wings, etc., more or less free from the body; biting mouthparts show- ing 74 73. Proboscis long; four wing-cases; sometimes in a cocoon. .Pupse of Lepidoptera Proboscis short; two wing-cases Pupse of Diptera 74. Prothorax small, fused into one piece with the mesothorax; sometimes enclosed in a loose cocoon Pupse of Hymenoptera Prothorax larger and not closely fused with the mesothorax 75 75. Wing-cases with few or no veins Pupae of Coleoptera Wing-cases with a number of veins Pupae of Neuropteroid Order* ORDER GRYLLOBLATTOIDEA. Elongate, flattened, wingless insects measuring over one inch in length. Head nearly horizontal, free, eyes small, no ocelli, anten- nae long and thread-like, arising from the front of the head, mandi- bles strong; prothorax large, quadrate, free; legs formed for run- ning, similar, coxse close together, tarsi five- jointed; cerci long, filiform, eight-jointed, ovipositor long and sword-shaped. (Grylloblatta.) (PI. 2, fig. 19.) GRYLLOBLATTID^ ORDER ORTHOPTERA. (ULONATA, part; SALTATORIA.) Small to large, jumping species usually possessing a device on the wings for making a creaking sound; hind femora almost always very much stouter basally, or longer, or both, than the middle femora; wings of adults reposing over the abdomen, the fore wings toughened, narrower and thicker than the membranous, plaited hind pair; sometimes the wings vestigial or completely absent; head usually vertical; ovipositor almost always free; mouthparts conspicuous, mandibulate; metamorphosis gradual, the young resembling the adults, but with the small wings in a reversed position in the last two nymphal stages, the hind wings then overlapping the fore wings. 1. Antennae almost always shorter than the body, generally thread-like and never distinctly tapering, joints distinct, often flattened; ocelli three; tarsi three- jointed, alike on all the legs; ovipositor short; auditory organs, if present, at the base of the abdomen 2 Antennae generally longer than the body, filamentous, delicately tapering; ocelli often absent; ovipositor usually long; auditory organ usually near base of front tibiae 3 2. Claws with a pad (arolium) beneath and between them; pronotum at most extending over only the extreme base of the abdomen (PI. 1, fig. 7); fore wings generally well developed. Locusts, Grasshoppers. (Melandplus [M. spretus, Rocky Mountain locust], Chortophaga, Hippiscus, Dissosteira \D. Carolina, Carolina locust].) (PL 1, fig. 8) ACRIDilD^ Claws without arolium; pronotum extending over the abdomen (PL 1, fig. 6); fore wings vestigial, consisting of small scales at the base of the usually large hind wings. Grouse-locusts, Pigmy locusts. (Tettix) (PL 1, figs. 10, 11.) TETTIGID^E 13 14 Key to Families of North American Insects. 3. Tarsi four-jointed; ovipositor usually long and sword-shaped; ocelli generally absent; fore wings, when present, with the sides sloping. Katydids, Green or long-horned grasshoppers. (Scudderia, Conocephalus, Ceuth6philus [Cave-cricket].) (PI. 1, figs. 2, 3, 4.) (TETTIGONIDM, PHASGON- URIDM) LOCUSTDX& Tarsi three-jointed; ovipositor, when present, exserted and needle-shaped, sometimes upcurved or with the tip enlarged; fore wings, when present, flat above, and with the sides bent abruptly downward. (GRYLLODEA) . . .4 4. Front legs more or less broadened and fitted for burrowing; females without ovipositor 5 Front legs slender, fitted for walking; female with needle-shaped ovipositor, which may sometimes be reduced in size. Crickets. (Gryllus, CEcanthus [Tree crickets], Myrmecophila.) (PL 1, figs. 12, 13.) (ACHETIDJS) GRYLLIDJE 5. Two large ocelli; front tibiae dilated, their outer edge strongly toothed; hind femora scarcely enlarged; tarsi three-jointed; over 25 mm. in length. Mole crickets. (Gryllotalpa.) (PI. 1, figs. 9, 14.) GRYLLOTALPKLE Three small ocelli; front tibiae scarcely dilated, but with three or four strong spines at apex; hind femora greatly enlarged; tarsi one-jointed; less than 10 mm. in length. (Tridactylus.) (PI. 1, fig. 5.). . . .TRTOACTYLIDjE ORDER PHASMOIDEA. (GRESSORIAL Large, wingless, slow-moving, slender, plant-eating insects with long, thin legs. Body narrowly cylindrical, head rather hori- zontal, generally rounded, ocelli often absent; mouth rather anterior, mandibles strong, antennae coarse, comprising more than twenty joints; prothorax very short, front legs similar to the others, coxse small and distant, tarsi five-jointed; cerci present but unsegmented. Metamorphosis very slight. Walking-sticks. Diapheromera, Bacillus.) (PI. 1, fig. 1.) PHASMID^ ORDER DIPLOGLOSSATA. (DERMODERMAPTERA .) Moderate sized, flattened, wingless species parasitic on rodents. Head movable, rather horizontal, mouth underneath, mandibles strong, no eyes, antennae short; prothorax free, large; legs alike, tarsi three-jointed; cerci long, but unsegmented. Metamorphosis imperceptible. One family HEMIMERIDJE, restricted to South Africa. Dermaptera — Thysanoptera. 15 ORDER DERMAPTERA. (EUPLEXOPTERA; EUDERMAPTERA.) Elongate, but small insects with the abdomen terminating in a pair of strong movable forceps. Fore wings horny, but short, hind wings large, nearly circular, radially folded from near the center (PI. 1, fig. 18), when folded, projecting slightly beyond the upper pair; mouth mandibulate; antennae long and slender. Metamor- phosis incomplete. Earwigs. 1. Metapygidium and telson not reduced, nearly as large as the pygidium which is relatively small; head depressed, truncate or concave posteriorly; femora compressed and usually keeled; tropical earwigs. (Pyragra, Pyragr6psis.) (PI. 1, fig. 15.) PYGEDICRANIIXflE Metapygidium and telson much reduced, very greatly smaller than the pygidium which is relatively very large and sometimes with complex processes 2 2. Metapygidium and telson although reduced in size, still present as distinct plates, if sometimes lost in the pygidium, the latter is fused with the last dorsal segment to form a horizontal squamopygidium; femora not com- pressed or keeled; head gently convex. (Anisolabis, Labidura.) (PI. 1, fig. 17.) LABIDURIDjE Metapygidium not distinct; pygidium well developed, often provided with com- plex processes 3 3. Second joint of tarsi simple, not lobed nor dilated. (Labia, Prolabia.) LABUDM Second joint of tarsi with a dilated lobe on each side. (Forficula, D6ru.) (PI. 1. fig. 16.) FORFICULIIX& ORDER THYSANOPTERA. (PHYSOPODA.) Small or minute, slender species with the wings often absent or reduced in size, feeding usually on plant sap. Head vertical, free; eyes well developed; usually three ocelli; mouthparts fitted for sucking, inferior, frequently asy metrical; pro thorax free; wings, when present, very narrow, usually with long marginal fringes, the venation greatly reduced; legs similar, tarsi one- or two-jointed, with a bladder-like or hoof -like enlargement at tip; no cerci. Metamorphosis gradual, the young very similar to the adult. 1. Female with a saw-like ovipositor (PI. 2, fig. 31); last segment of female abdo- men conical, that of the male broadly rounded; wings usually present, the fore pair strongest, usually with more or less well developed veins and 16 Key to Families of North American Insects. always at least one longitudinal vein reaching from base to apex; wing membrane with microscopic hairs. (Suborder TEREBRANTIA) 2 Female without a modified ovipositor, the last segment of the abdomen tubular in both sexes; wings often absent, both pairs similar in structure, the fore wings with only a median longitudinal vein which does not reach to the tip of the wing; wing membrane without microscopic hairs. (Suborder TUBULIFERA.) (Phlceothrips, Trichothrips, Cryptothrips.) PHLCEOTHRIPIIXE •2. Ovipositor curved upwards; fore wings broad, rounded and with prominent veins; antennae nine-jointed, (^dlothrips) JSOLOTHRIPID.&) Ovipositor curved downwards; wings when present usually narrow and pointed at tips; antennae seven- to ten-jointed. (Thrips [T. tdbaci, Onion Thrips] Eftthrips [E. pl/ri, Pear Thrips; E. tritid, Strawberry Thrips], Heliothrips [£T. hcemorrhoidaUs, Greenhouse Thrips].) (PI. 2, figs. 21, 31.) THRIPIDJE ORDER MANTOIDEA. Large, poor-flying, deliberate-moving, predatory species with long, spined front legs, which are formed for grasping prey. Body elongate; head freely movable, not inserted in the prothorax, eyes prominent; three ocelli; mouth inferior, mandibles strong, antennae filament-like, comprising many similar joints; prothorax always lengthened and movable; wings dissimilar, overlapping on the abdomen; cerci jointed. Metamorphosis incomplete. Praying Mantis. (Stagmomantis.) (PI. 2, fig. 22.) MANTID^E ORDER BLATTOIDEA. (OOTHECARIA, CURSORIA.) Moderate-sized, broadly oval, flattened, quick-running insects. Head free but inflexed so as to be nearly or quite concealed be- neath the pronotum, the mouth posterior or nearly so, mandibles strong, usually two ocelli; antennae long, filamentous, many- jointed; prothorax large, movable, usually transverse; wings when present overlapped on the abdomen; fore wings parchment- like, containing many veins, hind wings radially folding; legs strong, alike, coxae large; cerci prominent and jointed. Metamor- phosis slight. Roaches. (Phyliodrdmia, (=Blattella) [P. germdnica, Croton bug], Periplaneta, Isch- noptera, Blatta.) (PL 2, figs. 23, 25.) BLATTID^E Zoraptera — Isoptera — Corrodentia. 1 7 ORDER ZORAPTERA. Minute, wingless, agile, terrestrial, predatory species. Body flattened, head somewhat inclined, antennae moniliform, nine- jointed, mandibles strong, eyes vestigial; thorax as long as the ab- domen, pro thorax large; abdomen with ten segments, cerci one- jointed; legs similar, formed for running, tarsi two- jointed. One family, ZOROTYPID^, restricted to the East Indies. (PL 2, fig. 26.) ORDER ISOPTERA. Small to middle-sized, elongate, feeble insects living in colonies and occurring as sexual individuals, soldiers and workers; usually with weak chitinization. Head large, free, rather vertical, eyes and ocelli present or absent, mandibles often large, antennae filamentous; pro thorax large, free; legs similar, formed for run- ning, tarsi apparently four-jointed; wings similar, narrow and long, superimposed over the abdomen, soldiers and workers wing- less; cerci short. Metamorphosis very imperfect. White ants, Termites. Tarsi with an apical sole-like pad; eyes present, mandibles toothed; pronotum flat; wings reticulate; fontanel absent. (Termopsis, Calotermes.) PROTERMITIDjE Plan tula absent; mandibles not strongly toothed; pronotum convex; wings not strongly reticulate; vertex with fontanel. (Termes, Eutennes.) (PL 2, figs. 24, 27, 28.) (METATERMITIDJE) TERMITIDJE ORDER CORRODENTIA. (PSOCOPTERA, COPEOGNATHA.) Small or minute, mandibulate insects with long slender antennae, the body rather stout, the prothorax small, tarsi two- or three- jointed. Metamorphosis incomplete. Wings well developed; ocelli present. Bark living insects. (Csecilius, Psdcus.) (PL 2, fig. 29.) PSOCIDjE Wings absent, or at most a single small pair of mesothoracic wings present; ocelli absent. (Tr6ctes, [T. divinatbria, Book-louse], Atropos, Psocinella.) (PL 2, fig. 30.) i ATROPHY 18 Key to Families of North American Insects. ORDER MALLOPHAGA. (LIPOPTERA.) Small wingless insects averaging two mm. and very rarely over five mm. in length. Body oval, or elongate, very strongly flattened; usually strongly chitinized and generally with a conspicuous color pattern of pale or yellowish markings contrasting with spots or bands of dark brown or black. Mouth anterior, mandibles strong, antennae three- to five-jointed; prothorax free; legs short, no cerci. Metamorphosis very incomplete. External parasites of birds, more rarely of mammals during entire life, feeding on feathers, fur or skin. (Bird Lice, Biting Lice.) 1. Antennae filamentous, exposed, three- or five-jointed; maxillary palpi absent; mandibles vertical; meso- and metathoracic segments usually fused. Suborder ISCHNOCERA 2 Antennae clavate or capitate, concealed, four-jointed; maxillary palpi four- jointed; mandibles horizontal; meso- and metathoracic segments with a sutural line usually visible. Suborder AMBLYCERA 3 2. Antennae three-jointed; tarsi with a single claw; infesting mammals. (Trichodectes [T. latus, Dog Louse].) TRICHODECTIIXE Antennas five-jointed; tarsi with two claws; infesting birds. (Docophorus, Nirmus, Lipeurus.) (PL 2, figs. 34, 35.) PHILOPTERIDjE 3. Tarsi with a single claw; infesting mammals. (Gyropus.) . . . GYROPODHLE Tarsi with two claws; infesting birds (except in a few cases). (Menopon, Trindton.) LIOTHEID^ ORDER SIPHUNCULATA. (ANOPLURA, PSEUDORHYNCHOTA, PARASITA, PHTHIRAPTERA, ELLIPOPTERA.) Small, more or less flattened, wingless parasites of mammals. Head free, horizontal; eyes reduced or absent; mouth anterior, comprising an unjoin ted, fleshy beak; antennae short; thorax fused; legs similar; tarsi single-jointed, forming a claw at the end of the tibia; no cerci; metamorphosis very slight. True lice. 1. Body flattened; spiracles only at each side of the mesothorax and on abdominal segments three to eight; antennae three- or five-jointed; tibia with a thorn- shaped projection 2 Body thick and stout; mesothorax and metathorax each with a pair of spiracles as well as abdominal segments two to eight; eyes absent; tibia with a stout, short, thorn-like projection; antennae four- or five-jointed; entire body sup- plied with thorn-like bristles. (Echinophthirius.) . . ECHINOPHTHIRinXffi Hymenoptera. 19 2. Eyes large, convex, distinctly pigmented; fulturae very strong and broad arms; proboscis short, hardly reaching the thorax. (Phthirius [P. ingvinalis, Crab-louse] Pediculus [P. cdpitis, Head-louse; P. vestimenti, Body-louse]), (PL 2, figs. 32, 33) .................................... PEDICULID^ Eyes very indistinct or wanting; fulturae very narrow and closely applied to the pharynx; beak very long. (Haematopinus [H. iirius, Hog-louse].) ORDER HYMENOPTERA. (PHLEBOPTERA.) Moderate sized, small or minute, rarely very large; four mem- branous wings, the fore pair larger and more completely veined; venation rather complete but not complex, sometimes greatly re- duced; mouth-parts mandibulate, but the maxillae usually adapted for lapping liquid food; antennae variable; ocelli present; pro- thorax not free; legs similar; tarsi usually five-jointed; abdomen usually with six or seven visible segments; no cerci; ovipositor of female usually sting-like, sometimes saw-like, occasionally greatly elongate. Metamorphosis complete; larvae legless in the higher forms. Habits variable, phytophagous, predatory, or parasitic. Saw-flies, Wood-wasps, Ichneumon-flies, Ants, Wasps and Bees. 1. Abdomen broadly sessile, attached over a large area (PL 4, fig. 83); larvae with legs present, usually well developed; trochanters two-jointed (PL 4, fig. 63); hind wing with three basal cells. Suborder CHALASTOGASTRA (=SYMPHYTA, SESSILIVENTRES, PHYTOPHAGA, TERE- BRANTIA) ..................... ............................ * ..... 2 Abdomen petiolate or subpetiolate, never broadly sessile (PL 4, figs. 76, 77); larvae legless; trochanters one- or two-jointed; hind wing with less than three basal cells. Suborder CLISTOGASTRA (= AP6CRITA) ....... 12 2. Fore wings with three radial cells, i. e. two radial cross veins present; antennae many jointed, but with the three basal joints strongly developed, the third very long. (Macroxyela, Xyela, Odontophyes) (PL 3, fig. 36) Fore wings with only one or two radial cells, only one or no radial crossvein present .......................................................... 3 3. Costal cell divided by a distinct longitudinal vein (the subcosta); antennae slen- der, becoming very thin apically, many- jointed; radial cell with one cross- vein. (Pamphflius) (= Lyda), Neurotoma, Bactr6cerus (LYDIDJE) PAMPHILilIXE Costal cell not divided ................................................. 4 4. Anterior tibiae with a single apical spur ................................... 5 Anterior tibiae with two apical spurs. Saw-flies. (TENTHREDINOIDEA.) . 8 20 Key to Families of North American Insects. 5. Fore wings with only two cubital cells; antennae inserted much below the lower margin of the eyes, beneath a frontal ridge; vertex tuberculate. (Oryssus) ORYSSIDJE Fore wings with three or four cubital cells 6 6. Pronotum nearly truncate or weakly emarginate behind; mesonotum short? not extending much beyond the anterior margin of the tegulae; abdomen more or less compressed; antennas filiform, many-jointed. (Cephus [C. pygmcnts, Wheat-stem Saw-fly], Janus.) CEPHID^ Pronotum deeply curved or emarginate behind; mesonotum longer, extending well beyond the anterior margin of the tegulae 7 7. Parapsidal furrows present; fore wings with a transverse intercostal vein; no triangular plate at the apex of the abdomen; prothorax conical. (Xiphydria.) XIPHYDRinXE Parapsidal furrows absent; fore wings without an intercostal vein; apex of abdomen with a triangularly shaped plate; prothorax subquadrate. (Tre- mex, Sirex, Paurfcrus) (PI. 3, fig. 39) (UROCERIDft) SIRICnXE 8. First parapterum (a small, more or less triangular plate just behind the pro' thoracic spiracle and above the mesopleura) present 9 First parapterum absent; mesosternum not separated from the mesopleura by an impressed line (Acordulecera) PTERYGOPHORID.flJ 9. Abdomen angled laterally so that the dorsal sclerites are sharply divided into a dorsal and ventral surface; antennae clubbed. (Cimbex \C. americana, Willow Saw-fly], Trichiosdma, Zaraea) CIMBICIIXE Abdomen not sharply angled laterally; antennae not clubbed 10 10. Mesopleura separated from the mesosternum by an impressed line; antennae three- jointed, the third joint very long (Hylotoma(= Arge), Sterictiphora) HYLOTOMHXE Mesopleura not separated by an impressed line; antennae with more than six •joints 11 11. Antennae serrate (female) or pectinate (male), eighteen- to twenty-six-jointed. (Diprion (= Lophyrus) [Pine Saw-flies] DIPRIONHXE; Antennae filamentous, with seven to twelve, usually nine, joints. (Dolerus, Nematus, Macrophya, Tenthredella) (PI. 3, fig. 37). .TENTHREDINID^; 12. Hypopygidium divided, or never closely united with the pygidium, the ovi- positor issuing some distance before the tip of the abdomen, from its ventral surface (PI. 4, fig. 79) 13 Hypopygium entire and closely united with the pygidium, the sting or qvi- positor always issuing from the tip of the abdomen (PI. 4, fig. 82) 44 13. Winged 14 Wingless 25 14. Fore wings with a stigma which is rarely very slender or linear; costal vein well developed as far as the stigma (PI. 3, figs. 42, 43); abdomen usually with the ventral segments membranous and with a median fold; antennae usually with more than sixteen joints; wing venation ordinarily well de- veloped. (ICHNEUMON01DEA.) 15 Hymenoptera. 21 Fore wings without a stigma, the marginal vein if present, linear, not stigmated; costal vein entirely absent or much thinner than the subcostal (PI. 3, figs. 44, 46); abdomen with the ventral segments hard and chitinous, without a median fold; antennae with not more than sixteen joints (in our genera); wings with very incomplete venation 22 15. Costal and subcostal veins separated, enclosing a narrow costal cell (PI. 3, fig. 38) 16 Costal and subcostal veins confluent, no costal cell (PI. 3, fig. 42) 18 16. Abdomen inserted on the thorax far above the hind coxae; antennae with thir- teen or fourteen joints. (Foenus, Evania, Pristaulacus) (PI. 3, figs. 38, 43). EVANIIIXE Abdomen inserted normally, low down and quite close to the hind coxae. . .17 17. Antennae fourteen-jointed; body of the abdomen beyond the petiole compressed, ovate or rounded; ovipositor short. (Roprfinia.) ROPRONIID^ Antennae very slender, with thirty joints or more; abdomen elongate; ovipositor long. (Stephanus.) STEPHANIES 18. Mandibles abnormal, their attachment reversed so that the cutting edges face outward, laterally instead of inward, and so do not meet when the jaws are closed. (Dacnfisa, Aphaereta, Alysia.) ALYSITO^ Mandibles normal, their tips meeting when closed 19 19. Ventral abdominal segments soft and membranous, with a median fold 20 Ventral abdominal segments hard, chitinous, without a median fold; second and third segments covering most of the abdomen. (Myersia, Thaumatotypidea.) MYERSIKLE 20. Front wings with two recurrent nervures (except in the rare genus Pharsalia); none of the dorsal abdominal segments fused together, all freely movable. (Ichneumon, Cryptus, Limnerium, Ophion, Tryphon, Pimpla) (PI. 3, fig. 42; PI. 4, fig. 63; PI. 5, fig. 85) ICHNEUMONUX® Front wings with only one recurrent nervure (PI. 3, fig. 40); second and third segments of abdomen usually immovably united 21 21. Abdomen inserted on the thorax high above the hind coxae; rare insects. (Cap- itdnius (= Cenoccelius).) CAPITONmXE Abdomen inserted close to the hind coxae; a very extensive group. (Lysiphlebus, Meteorus, Chelonus, Microgaster, Bracon, Rhogas) (PI. 3, fig. 40; PI. 4, fig. 76) BRACONIDJE 22. Sides of the pronotum extending back to the tegulae; antennae not elbowed. Gall Flies. (CYNIPOIDEA.) 23 Pronotum not extending back to the tegulae (PI. 4, fig. 73); antennae more or less distinctly elbowed. Chalcis Flies (CHALCIDOIDEA.) 30 23. Dorsal abdominal plates meeting along the venter, and entirely enclosing all the ventral plates, except sometimes a part of the hypopygium. (Euc6ila, A116tria.) FIGITID^E Dorsal abdominal plates usually extending well down on the sides of the abdo- men, but not meeting along the venter; all or nearly all of the ventral plates visible... ...24 22 Key to Families of North A merican Insects. 24. Basal joint of hind tarsi twice as long as the others united, the second with a long, spined process externally; abdomen greatly compressed, curved like a pruning knife, much longer then the remainder of the body. (Ibalia.) IBALIID^E Basal joint of hind tarsi much shorter; second joint simple. (Andricus, Hol- caspis, Neur6terus, Synergus) (PL 3, fig. 46) CYNIPID^E 25. Antennae distinctly elbowed (PL 4, figs. 69, 70, 71). A few genera distributed among the families of Chalcidoidea. (See couplet 30.) Antennae not elbowed (PL 5, fig. 85) 26 26. Mandibles in a reversed position, the tips extending laterally and not meeting when closed (see couplet 18.) A few ALYSIID^E Mandibles attached normally 27 27. Abdominal petiole expanded apically, not cylindrical (PL 5, fig. 85.) 28 Abdominal petiole cylindrical (see couplet 22.) A few CYNIPOIDEA 28. Ventral abdominal segments soft, with a median fold 29 Ventral segments hard, without a fold. (See No. 19.) . . . .MYERSfflXE, part 29. All dorsal abdominal segments free. (See couplet 20.) A few ICHNEUMONID^E Second and third dorsal segments usually immovably grown together. (See couplet 21.) A few BRACONID^ 30. Hind wings exceedingly narrow, linear, the base forming a long stalk; oviposi- tor issuing barely before the tip of the abdomen; antennae with the scape not elongated, compressed, and without ring joint; very minute species with long wing-fringe. (Polynema, Gonat6cerus.) MYMARID^E Hind wings never very narrow, not linear or pedunculate at the base; ovipositor issuing decidedly before the tip of the abdomen; antennae elbowed (PL 4, figs. 69, 70, 71), with long scape and usually with from one to three ring joints 31 31. Tarsi five-jointed (rarely four-jointed or less in certain wingless males); axillae with their anterior margin usually straight and not produced anterior to the tegulae (PL 4, fig. 68); spur of front tibia strong 32 Tarsi three- or four-jointed (five-jointed or heteromerous only in the females of one or two genera) ; axillae produced forward, their front margin opposite or anterior to the tegulae (PL 4, fig. 73); spur of front tibia usually weak. . . .42 32. Head of female long, oblong, with a deep longitudinal groove above; front and hind legs very stout, middle ones very slender or aborted; males wingless with short three- to nine-jointed antennae. Fig insects, mainly tropical. (Blastophaga, Eiseniella.) AGAONID. the stigma narrow; female with the radial cell in the fore wing closed and often separated from the costa (PI. 3, figs. 48, 49). (Myzine.) MYZINID^E Male with the pygidium entire, the stigma broad; female with the radial cell in the fore wing usually open and the first discoidal cell not elongated; eyes entire in both sexes. (Tiphia, Paratiphia.) TIPHIID^; 69. Hind wings with an anal lobe, separated by a deep linear notch 70 Hind wings without an anal lobe, at most obtusely emarginate on the posterior basal margin 71 70. Fore wings with the radial and the first and second discoidal cells very long, each fully four times as long as high; abdomen with a long, claviform petiole; rare West Indian insects. (Rhopalosdma.) RHOPALOSOMATID^; Fore wings of a different conformation; abdomen either petiolate or sessile. (Myrmdsa, Chyphotes.) Males of the MYRMOSHXE Hymenoptera. 2*7 71. Cubitus in hind wing originating at or beyond the transverse median nervure; our species small, with shining body. (Sierolomorpha.) COSILID^ Cubitus in hind wing arising far before the transverse median nervure; body almost always conspicuously pilose (PL 3, fig. 45). (Mutflla, Sphseroph- thalma, Ephfita, Pseudomethdca) Males of the MUTILLID^; 72. Thorax undivided, the pro-, meso- and metathorax consolidated into a single piece, without visible sutures between them. (See couplet 71.) Females of the MUTILLDXflE Thorax with at least one complete transverse suture 73 73. Thorax divided into two parts. (See couplet 70.) Females of the MYRMOSDXE Thorax divided into three parts 74 74. Head long, usually distinctly longer than broad, flattened above, the front horizontal; legs stout. (See couplet 58.) . . Some females of the BETHYLID^ Head transverse, subquadrate or rounded 75 75. Antennae twelve-jointed; anterior tarsi not pincers-shaped (Methdca) THYNNIDJE Antennae ten-jointed; front tarsi usually pincers-shaped (PL 5, fig. 92). (Gon- atopus.) (See couplet 59.) DRYINUXE, part Antennae thirteen-jointed; wings present as small pads (See No. 71.) A few male MUTILLnXE 76. Hind tarsi slender, filiform, the first joint not broadened or thickened; hairs on body simple. Wasps 77 Hind tarsi with the first joint thickened or flattened, often densely hairy; hairs of body feathery or branched. Bees 93 77. Middle tibiae with a single apical spur, or rarely with none 78 Middle tibiae with two spurs 86 78. Fore wings with only one cubital cell which is sometimes fused with the first discoidal (PL 3, fig. 58) 79 Fore wings with two or three cubital cells (PL 3, fig. 52) 81 79. Eyes not emarginate 80 Eyes deeply emarginate within, a second cubital cell indistinctly defined. (See couplet 82.) TRYPOXYLONID^; 80. First cubital cell separated from the first discoidal; scutellum and postscutel- lum simple, without spines or scales, eyes divergent above. (Crabro, Ana- crabro.) CRABRONID^; First cubital and first discoidal cells confluent; scutellum with a marginal lam- ella on each side; postscutellum with a spine or forked process; eyes con- vergent above. (Oxybelus, Notoglossa.) OXYBELED^ 81. Abdomen strongly constricted between the first and second segments 82 Abdomen without a strong constriction between the first and second seg- ments 83 82. Fore wings with two cubital cells; the second usually weakly defined, some- times not indicated; abdomen petiolate, long, slender, and enlarged apically; eyes deeply emarginate within. (Tryp6xylon.) TRYPOXYLONID^E 28 Key to Families of North American Insects. Fore wings with three cubital cells; second often petiolate; abdomen sessile or subsessile, usually constricted between the segments; eyes rarely emargin- ate (PI. 3, fig. 54). (PhMnthus, Cerceris, Eucerceris.) . . PHILANTHIIXS 83. Abdomen sessile .................................................... 84 Abdomen petiolate or subpetiolate; two or three cubital cells, transverse median nervure not S-shaped, hind wing usually twice emarginate on the basal half of the posterior border; usually rather small black species. (Psen, Cemfinus, Stigmus, Passaloecus.) (Including MIMESID.E and PEMPHREDOXID^E.) 84. Labrum large, free, triangularly elongated beyond the clypeus, much longer than wide; radial cell not di vided near the apex; ocelli more or less aborted (PI. 3, fig. 52). (Bembex, Monedula, Microbembex.) ....... BEMBECIIXE Labrum small, usually entirely concealed by the clypeus; radial cell usually divided by a crossvein near apex, the portion beyond the crossvein less clearly defined; at least the front ocellus perfectly formed ............. 85 85. Second cubital cell petiolate, very rarely absent; third either present or absent; three perfectly formed ocelli; small species. (Miscophus, Plenoculus.) NITELID^E Second cubital cell present not petiolate; hind ocelli frequently aborted (PI. 3, fig. 51; PI. 5, figs. 87, 89). (Astata, Lyroda, Tachysphex, Tachytes.) 86. Abdomen with a more or less distinct constriction between the first and second segments, the first segment broader at tip than at base; middle coxae in contact; second cubital cell not receiving a recurrent nervure; rare species. (Mellinus.) ............................................ MELLINnXE Abdomen not constricted between the first and second segments; middle coxae separated by the sternum (some metallic green Chrysididae (see couplet 57) may lead out here; they have the abdomen sessile, with less than six dorsal segments, and the pronotum though long does not quite reach the tegulse) . 87 87. Mesosternum produced into a forked process posteriorly, the mesepisternum not separated; parapsidal furrows distinct; pronotum conically produced in front. (Rhin6psis.) ................................. AMPULICID^ Mesosternum not produced backwards, the mesepisternum separated; parap- sidal furrows indistinct or absent; pronotum not conically produced ..... 88 88. Abdomen with a distinct slender, nearly cylindrical petiole (PI. 3, fig. 57; PI. 4, figs. 75, 77). (Chalybion, Sceliphron (=Pelopceus) Sphex (= Amm6phila) . Chlorton (= Sphex, Priondnyx, Isod6ntid) .................. SPHECDX& Abdomen sessile or subsessile, never with a slender petiole ................ 89 89. Labrum free, well developed, triangular or semicircular, wider than long. (Stizus, Sphecius.) ........................................ STIZID^E Labrum short, not or scarcely exserted beyond the clypeus ................ 90 90. Marginal cell broadly truncate at apex and prolonged as a small, weakly defined cell; antennae inserted close to the clypeus or very close to the clypeal suture. (Astata, Diploplectron) ........ Subfamily ASTATINE of the NYSSONTD-flS Marginal cell pointed at apex, not appendiculate; antennae inserted far above the clypeus, always away from the clypeal suture .................... 91 Hymenoptera. 29 91. Fore wings with the second cubital cell petiolate, rarely triangular; meso- pleural furrow wanting or indicated only anteriorly .................... 92 Fore wings with the second cubital cell broadly sessile, not triangular, receiv- ing both recurrent nervures; mesopleural furrow complete, usually deep (PI. 3, fig. 56). (Pseudoplisus, Gorytes, Hoplisddes.) ...... GORYTIDjE 92. Metathorax with the upper hind angles acute or produced as stout spines ; pro- notum short medially, strongly transverse; short, stout species. (Nysson, Brachystegus) ......................................... NYSSONDXE Metathorax with the hind angles rounded or obtuse; pronotum subquadrate; slender species. (Alyson, Didineis) ...................... ALYSONID^E 93. Hind tibiae without apical spurs; eyes hairy; marginal cell very long. (PL 4, fig. 81; PL 5, fig. 91.) (Apis [A. mellifera, Honey-bee]) ........... APEX® Hind tibiae with apical spurs .......................................... 94 94. The cheeks separating the eyes from the mandibles longer than the pedicel of the antennae; social bees; large, densely hairy species with contrasting black and yellow or sometimes also orange pile. Bumble-bees. (B6mbus,Psithyrus) Eyes nearly or quite reaching to the base of the mandibles; solitary bees of different appearance .............................................. 95 95. Tongue short, broad, obtuse and emarginate at apex (COLLETIFORMES) . . 96 Tongue more or less elongate, pointed and not emarginate; no ventral abdom- inal brush of hairs. (ANDRENIFORMES) .......................... 97 Tongue long and very slender. (PL 5, fig. 91.) .......................... 99 96. Black bees with little hair; fore wings with only two cubital cells; face almost always with yellow or white markings; nearly always small species. (Pro- sdpis) ................................................ PROSOPHXiE Hairy bees; fore wings with three cubital cells; moderate-sized species. (Col- Idtes) ................................................ COLLETIDjE 97. Tongue more or less short, dagger-like; radial cell pointed; usually three cubital cells; maxillary palpi six-jointed; burrowing bees. (Andrena, Halictus, Augochl6ra, Agap6stemon, SphecSdes.) ................... ANDRENID^) Tongue elongate, though not so long as in some of the higher groups ; only two submarginal cells (except in Protandrena which has three) ; never brilliantly metallic, though rarely with the head and thorax green; often with yellow markings. (Panurgus) ................................ PANURGIDjE Tongue elongate; parasitic bees, usually highly ornamented, and with no pol- len-collecting apparatus ........................................... 98 Tongue very long; first two joints of labial palpi elongate, sheath-like, last two minute; hairy, pollen-collecting bees, the males often with long an- tennae, and usually with the clypeus yellow. Melissddes, Anthophora, Hemisia (= Centris), Diadasia) ..................... ANTHOPHORID^E 98. Maxillary palpi six-jointed; usually wasp-like in appearance, with bright yel- low and often red colors; almost always with three cubital cells; marginal cell pointed on costa. (N6mada) .......... ............... NOMADIDjE Maxillary palpi two- to six-jointed; usually robust bees with conspicuous mark- ings due to hair, but without yellow tegumentary markings. (Epeolus, Triepeolus, Bombomelecta, Neopasites.) .................. MELECTIIXE 30 Key to Families of North American Insects. 99. Fore wings with two cubital cells; labial palpi with the basal joints much elon- gated, the apical minute; underside of abdomen of female with a pollen- collecting scopa, except in the parasitic genera. (Coelioxys, Megachile, Heriades, Osmia, Stelis, Anthidium.) MEGACHILIDjE Fore wings always (in our species) with three cubital cells, the marginal cell narrow and as long as the cubitals united 100 100. Hind tibia and tarsus of female with a dense pollen-collecting scopa; stigma obsolete; large robust bees, mainly tropical. (Xyl6copa) . . XYLOCOPIDJE Hind tibia and tarsus of female without distinct scopa; stigma large; small bees. (Ceratina) CERATINID^E ORDER COLEOPTERA. (ELEUTERATA; ELYTHROPTERA.} Moderate-sized, small or minute, more rarely very large, hard- bodied insects; head free, usually prominent; mandibles well developed; antennae ten- or eleven-jointed, sometimes less, very rarely more; ocelli nearly always absent; pro thorax free; two pairs of wings, the front pair (elytra) thickly chitinized, sheathing the meso- and metathorax and also nearly always the abdomen, almost always meeting in a straight line down the middle of the back; hind wings occasionally absent; legs homonomous, the tarsi usually with five or four joints; no cerci. Metamorphosis com- plete, the larva? mandibulate. A very large and widely distributed group, including beetles and weevils. 1. First ventral segment divided by the hind coxal cavities (except the rare Cupe- didse) so that the sides are separated from the very small median part, the first three ventral segments immovably united; antennae thread-like or nearly so; hind wings with one or two crossveins near the middle, connecting the first and second branches of the media (PI. 7, figs. 158, 159); almost always carnivorous and predatory. Suborder ADEPHAGA 2 First ventral segment visible for its entire breadth; wing without such cross- veins (PI. 7, figs. 160, 161). Suborder POL^PHAGA 8 2. First three ventral segments immovably united 3 Abdomen with five free ventral segments; metasternum with a piece in front of the hind coxae marked off by a distinct suture; rare bark beetles. (Cupes.) CUPEDID^ 8. Metasternum with a transverse triangular antecoxal sclerite separated by a well marked suture, reaching from one side to the other and extending between the hind coxae (PI. 6, fig. 108) 4 Metasternum with a short antecoxal sclerite, not prolonged posteriorly between the coxse, the suture indistinct; rare semiaquatic beetles. (Amphizda.) AMPHIZOIILE Coleoptera. 31 Metasternum without an antecoxal sclerite 6 4. Antennae eleven-jointed; hind coxae movable and simple; terrestrial 5 Antennae ten-jointed; hind coxae fixed, expanded so as almost to conceal the base of the abdomen (PL 4, fig. 124); small water beetles. (Cnemiddtus, Haliplus.) HALIPLIIX® 5. Antennae inserted on the front, above the base of the mandibles; eyes promi- nent; head vertical, wider than the thorax. Tiger-beetles. (Cicindela, Omus, Tetracha.) CICIKDELID^ Antennae inserted on the sides of the head, between the base of the mandibles and the eyes; head usually held horizontally and generally narrower than the thorax. Ground beetles. (Omophron, CalosSma [Caterpillar-hunter], Bembidium, Platynus, Brachinus [Bombadier beetle], Pter6stichus, Har- palus, Chlamius) (PL 5, fig. 97; PL 6, fig. 108; PL 7, figs. 158, 164). CARABIIXE 6. Metasternum prolonged behind as a triangular process; aquatic 7 Metasternum not prolonged between the coxae; scutellum absent; antennae formed like a string of beads; rare bark beetles. (Rhysddes) (PL 7, fig. 146.) RHYSODIDvE 7. Antennae slender, abdomen with six segments; eyes two. Diving beetles, Water-tigers. (Dytiscus, Cybfster, Acflius, Agabus, Colymbetes) (PL 5 fig. 101) DYTISCnXE Antennae short, abdomen with seven segments; eyes four. Whirligig beetles. (Gyrinus, Dinettes) (PL 6, fig. 117; PL 7, fig. 147) GYRINnXffi 8. Antennae clubbed or not, if clubbed, not lamellate 9 Antennas with the last three to seven joints enlarged on one side to form a comb- like or lamellate club which can often be opened and closed (PL 7, figs. 149, 150, 151) ; legs often fitted for digging; tarsi almost always five-jointed, front tarsi of some dung beetles may be absent; larvae with thick curved body and well-developed legs. (LAMELLICORNIA.) 114 9. Head not prolonged into a beak; palpi flexible, gular sutures double, at least before and behind; prosternal sutures distinct, proepimera not meeting behind the prosternum 10 Head generally prolonged and snout-like (PL 6, fig. 125), palpi nearly always rigid; gular sutures confluent medially; proepimera united behind the pro- sternum, prosternal sutures wanting, antennae often elbowed; fourth tarsal joint usually indistinct; larvae legless or with short legs. (RHYNCHOPHORA.) 110 10. Fourth and fifth tarsal joints not immovably united, the articulation between them like those between the other joints (PL 7, figs, 143, 168) (If rarely immovably united as in some Erotylidae, the antennae are clavate) 11 Fourth tarsal joint minute, fused with the fifth; tarsi usually densely pubes- cent below, the first three joints dilated and with a sole, the third joint usually bilobed (PL 7, figs. 157, 167); antennae thread-like, rarely serrate or thickened apically; plant feeders. (PHYTOPHAGA.) 108 11. Hind tarsi with at least as many joints as the others 12 Hind tarsi four-jointed, front and middle tarsi five-jointed. (HETER6MERA.) 86 32 Key to Families of North American Insects. 12. Maxillary palpi slender, almost always as long as or longer than the antennae; antennae six- to nine-jointed, the outer joints forming a pubescent, distinct club; usually aquatic, convex beetles. Larvae usually with cerci. (PAL- pic6RNiA.) Water scavenger beetles. (Hydr6philus, Laccdbius, Hydrdbius, Cercyon) (PI. 6, figs. 110, 111) HYDROPHILIDjE Maxillary palpi much shorter than the antennae; larvae never with cerci. (Di- VERSICORNIA, PoLYMOKPHA, or CLAVICORNIA and SERRICORNlA) 13 13. Elytra short, exposing much of the abdomen; dorsal segments of abdomen entirely horny in texture; wings usually present and folded beneath the elytra, crossveins absent -. 14 Elytra covering most of the abdomen, rarely much shortened, in which case the wings are wanting, or not folded beneath the elytra; dorsal segments partly membranous 15 14. Abdomen flexible, seven or eight ventral segments, body usually slender; scavengers. Rove beetles. (Stenus, Staphylmus, Tachyporus, Philonthus) (PI. 5, fig. 95) STAPHYLINnXE Abdomen not flexible, five or six ventral segments; small or minute, robust beetles. (Bryaxis, Batrisddes) (PI. 7, figs. 138, 148). . . .PSELAPHnxffi 15. Tarsi five-jointed on at least one pair of legs, and almost always on all pairs . . 16 All tarsi with less than five joints 65 16. Last tarsal joint long and with very large claws (PI. 7, fig. 143); first three ventral segments grown together; small aquatic or subaquatic beetles. (Psephenus, Dryops, Elmis) (DRYOPIDfi) PARNIIXE Tarsal claws normal; all ventral segments free except in the Colydiidae, Heter- oceridae, Buprestidae and some Byrrhidae which are not aquatic 17 17. Abdomen with five ventral segments 18 Abdomen with at least six ventral segments 50 18. Front coxae globular or transverse, usually projecting but little from the coxal cavity; trochanters never interstitial 19 Front coxae more or less conical and prominent 37 19. Front coxae transverse, more or less cylindrical 20 Front coxae globular 27 20. Hind coxae grooved to receive the femora 21 Hind coxae flat and not grooved 26 21. Strongly convex beetles with more or less retractile legs, tibiae dilated and usually grooved near the outer end to receive the tarsi, tibial spurs dis- tinct 22 Slightly convex oval species with non-retractile slender legs; tibial spurs more or less reduced 24 22. Antennas inserted at sides of head 23 Antennae inserted on front, head retracted; third tarsal joint lobed; thorax margined; oval tropical species (Chelonarium) CHELONARIED^; £3. Head prominent, men turn large, elongate and subelliptical; tarsi not lobed. (Nosodendron.) NOSODENDRTD^E Head retracted, mentum small and quadrate; (Amphicyrta, Byrrhus). BYRRHIDAE Coleoptera. 33 24. Front coxae with distinctly separated side-piece (trochantin). (Dascyllus.) DASCYLLIDJE Front coxa? without trochantin 25 25. Posterior coxae at most moderately dilated internally. (Cyphon) (PI. 7, figs. 127, 129.) (CYPHONIDJE.) HELODnXE Posterior coxae very large. (Eucinetus.) EUCINETIDJ2 26. Tarsi more or less dilated, the first joint not shortened, fourth joint very small; elytra usually not extending to the tip of the abdomen. (Carpophilus, Omosita, Nitidula) NITIDULIDyE Tarsi slender, metatarsus short; elytra entire, never truncate, covering the abdomen. (Tenebridides, Peltis) (PL 7, fig. 135) (TROGOSITIDJE, TEMNOCHILIDM.) OSTOMATIDJE 27. First and second ventral segments fused or immovably united; antennas serrate (pectinate in the male of Xenorhepis; tarsi with membranous lobes beneath; hard-bodied beetles, of more or less metallic color. (Chalcophora, Chrysobothris [C. femorata, Flat-head orchard-borer], Buprestis, Agrilus) (PL 5, fig. 93.) BUPRESTDXS; All ventral segments free, except in very rare cases 28 28. Prosternum prolonged behind into a process which is received in the meso- sternum v ... 29 Prosternum without such backwardly directed process 31 29. Prothorax loosely joined to the mesothorax, freely movable, its hind angles usually prolonged backward into teeth; prosternal spine loosely received in a notch in the mesosternum; front coxal cavities contained entirely in the prosternum 30 Prothorax firmly attached, not movable; front coxal cavities closed behind by the mesosternum. (Drapetes, Thr6scus.) THROSCID^E 30. Labrum visible; prosternum lobed in front; beetles capable of moving the prothorax by its basal joint with a sudden clicking motion. Click- beetles, Wireworm beetles. (Alaus, Elater, Melandtus, Drasterius, Limdnius) (PL 7, fig. 126, 128.) • ELATERnXE Labrum concealed; prosternum not lobed in front; antennae inserted on the front, somewhat distant from the eyes; not able to leap by the prothoracic joint. (F6rnax, Microrhagus) .EUCNEMHX/E 31. Hind coxae in contact; body very small, convex, oval or rounded-oval. (Phalacrus, Olibrus.) PHALACRHXE Hind coxae not in contact, although closely approximate in certain very much flattened species 32 32. Elytra shortened, leaving two segments of the abdomen uncovered, antennae elbowed, very strongly clavate; tibiae compressed, front pair usually toothed. (Hister, Saprinus, Hololepta) (PL 7, fig. 141.) .mSTERID^ Elytra entire 33 33. Tibiae dilated and toothed externally; large tropical beetles with strongly clubbed antennae. (Syntelia.) SYNTELIID.E Second radial arising distinctly before the apex of the cell, well away from the origin of the third radial 94 Lepidoptera. 59 94. Five veins extending from the cell to the costa in fore wing ............. 95 Four veins from cell to costa in fore wing, the fifth radial ending decidedly below wing-tip ................................................... 96 95. Second branch of media in hind wing arising decidedly nearer to the first than the third medial. (Ethmia.) ........................ ETHMIOXE Second medial vein in hind wing arising nearer the third medial, or rarely mid- way between the first and third. (Agnepteryx, Depressaria, Epicallima.) CECOPHORUXE, part 96. Fourth and fifth radial veins stalked; ocelli absent or vestigial (see couplet 95) ........................................... CECOPHORID./E, part All veins in fore wing arising separately, if the fourth and fifth radials are rarely stalked, the ocelli are large (see couplet 90) .YPONOMEUTID^E, part 97. Radius in fore wing five-branched, all arising from the discal cell; eyes strongly lashed in front; antennae separated at base by a distance greater than half the width of eyes, usually hooked at tip; small, rarely rather large, stout- bodied butterflies of rapid, erratic flight. Skippers (Pamphila, Nisoniades, Eftdamus, Megathymus.) (PI. 10, figs. 213, 219, 237) ..... HESPERIED^ Fore wings with some of the radials stalked or absent; eyes rarely lashed; antennae closer together, the antennal club never pointed and recurved at tip ........................................................... 98 S8. Front pair of legs, at least in the male, more or less strikingly different from the other pairs; usually not used for walking; the claws of their tarsi, when present, never toothed nor split .................................... 99 Front legs like the other pairs, or if slightly reduced in size and structure, with the claws toothed or bifid ........................................ 108 39. Front tarsus without claws in either sex (PI. 10, figs. 217, 218); front legs much reduced in size in both sexes, their tarsi in the male with only one joint; in the female usually with five joints ......................... 100 Front tarsus of female with claws, that of the male sometimes with a single claw; front legs never much reduced in size. (PL 10, figs 214, 215.) . . . .106 100. Discal cell of hind wings closed ...................................... 101 Discal cell of hind wings open ..................................... 105 101. Front foot of female ending in a corrugated knob; subcostal vein in fore wing forked at the extreme base; antennae not scaled above; generally large butterflies with rather bold contrasting coloration; mainly tropical. ( Anosia (=Danais) [A. archippus, Milkweed-butterfly]) (PL 10, fig. 235). (EUPLCEID&) LYMNADIDJE Front tarsus of female present, though more or less abbreviated. (PL 10, fig. 218.) ....................................................... 102 102. Fore wings twice as long as broad .................................... 103 Fore wings much less than twice as long as broad ...................... 104 103. Antenna? clothed with scales, at least above; front tarsus of female four- jointed; wings opaque; medium-sized, brightly colored butterflies with elongate oval wings; mainly tropical. (Apostraphia, Heliconius.) Antennas naked, wings often in great part translucent and destitute of scales; wings elongate, oval; mainly tropical. (Dircenna, Ithomia.) 60 Key to Families of North American Insects. 104. Some of the veins at the base of the fore wing greatly swollen; usually small butterflies, rarely rather large; frequently of brownish color with yellowish eyespots or ringed marks (Cercyonis (=Satyrus), Ccenonympha, En6dia (=Debu), Cissia.) (PL 10. fig. 218.) AGAPETID^ Veins not swollen at base of fore wing; large tropical species with very broad wings, above with deep, rich colors, below with eye-spots and intricate lines;, tropical, hi the United States only as accidental visitors. (Caltgo.) BRASSOLID^ 105. Hind wings with a cradle-like depression along the inner margin in which the abdomen rests; large species, usually with brilliant metallic blue c^lor; tropical. (M6rpho.) MORPHOUXE Hind wings without structure of this sort; usually moderate-sized species without brilliant blue coloration; many common brightly colored butter- flies. (Argynnis, Brenthis, Phyciddes, Polygdnia (=Grapta), Euvanessa (= Vanessa), Vanessa (=P