CLASSIFICATION 



Head louse, Pediculus 

 capitis, female. Length, 

 2 mm. 



FIG. 24. 



spicuous. Mouth parts mandibulate. FIG. 23. 



Prothorax large. Wings almost always 



four, membranous, subequal or else hind 



pair smaller, complexly reticulate, not 



plicate. Larvae thysanuriform or in 



some cases cruciform, and aquatic or 



terrestrial. Example, Chrysopa (Fig. 



24). About six hundred species have 



been named. 



ii. Mecoptera. Metamorphosis indi- 

 rect. Mouth parts mandibulate, at the 



end of a deflexed rostrum, or beak. 



Prothorax small. Wings four, elongate, 



membranous, naked, coarsely reticulate, 



or else rudimentary or absent. Larvae 



cruciform, caterpillar-like, with numerous prolegs, carnivo- 

 rous. Example, Bittacus (Fig. 25). A 

 single family, Panorpidae, comprising but 

 few known species. 



12. Trichoptera. Metamorphosis in- 

 direct. Antennae filiform. Mouth parts 

 of imago rudimentary or imperfectly 

 suctorial ; mandibles rudimentary or 

 absent. Prothorax small. Wings four, 



membranous, hairy, veins moderate in number, cross veins 



few; hind pair almost always 



the larger, with plicate anal 



area. Larvae suberuciform, 



aquatic, usually case-forming. 



Example, Molanna (Fig. 26). 



Between five and six hundred 



species are known. 



13. Lepidoptera. Metamor- 

 phosis indirect. Mouth parts 



suctorial, mandibles absent or 



rudimentary (except in a few 



Chrysopa plorabunda. 

 Slightly reduced. 



FIG. 25. 



Bittacus strigosus. Natural size. 



