1 8 ENTOMOLOGY 



branous, naked, coarsely reticulate, or else rudimentary or absent. 

 Larvae cruciform, caterpillar-like, with three pairs of thoracic legs and 

 often eight pairs of abdominal prolegs, carnivorous. Example, Bittacus 

 (Fig. 27). A single family, Panorpidae, comprising but few known species. 



16. Trichoptera. Metamorphosis indirect. Eyes prominent. 

 Antennae filiform. Mouth parts of imago rudimentary or imperfectly 

 suctorial; mandibles rudimentary or absent. Pro thorax small. Tarsi 

 five-segmented. Wings four, membranous, hairy, veins moderate in 

 number, cross veins few;' hind pair almost always the larger, with 

 plicate anal area. Larvae suberuciform, with three pairs of thoracic 

 legs, aquatic, usually case-forming. Caddis worms and caddis flies. 

 Example, Molanna (Fig. 28). Between five and six hundred species 

 are known. 



17. Lepidoptera. Metamorphosis indirect. Antennae long, of vari- 

 ous forms, many-segmented. Mouth parts suctorial, mandibles absent 

 or rudimentary (except in a few generalized species). Eyes well 

 developed. Ocelli sometimes present. Prothorax reduced. Tarsi 

 usually five-segmented. Wings four, large, similar, membranous, with 

 veins moderate in number, and few cross veins. Adults usually clothed 

 throughout with scales. Larvae cruciform (caterpillars), typically with 

 three pairs of thoracic legs and five pairs (sometimes fewer) of abdom- 

 inal prolegs, mandibulate, phytophagous (rarely carnivorous) . Butter- 

 flies and moths. Some fifty thousand species have been described. 

 Two suborders, not sharply separated from each other. 



Suborder Heterocera. Antennae of various forms, but not ter- 

 minating in a distinct knob or club. Frenulum usually present. 

 Chiefly nocturnal in habit. Example, Callosamia (Fig. 239). 



Suborder Rhopalocera. Antennas simple, terminating in a distinct 

 club and without conspicuous lateral processes. Frenulum absent. 

 Diurnal normally. Examples, Papilio (Fig. 29), Anosia (Fig. 247, A). 



18. Hymenoptera. Metamorphosis indirect. Mouth parts at the 

 same time mandibulate and suctorial. Prothorax usually small. Tarsi 

 usually five-segmented. Wings two pairs, similar, membranous, trans- 

 parent or translucent, without scales, with a few irregular veins and 

 cells; venation sometimes reduced; hind wings smaller than fore wings; 

 fore and hind wings held together by a series of hooks (hamuli). 

 Abdomen usually with six or seven evident segments. Females with an 

 ovipositor, modified for sawing, boring or stinging. Larvae cruciform, 

 mandibulate; caterpillar-like, with head and legs, or maggot-like and 

 apodous. Twenty-five or thirty thousand species. Two suborders. 



