INSECTS AND THEIR NEAR RELATIVES 27 



G. Wings fringed with long hairs. Size 

 usually less than one-eighth inch in 

 length. Mouth-parts indeterminate in 

 type. Thrips. Physopoda. 

 GG. Wings without fringes. Very easily 

 broken off or shed by the insect. Ter- 

 mites. Isoptera. 

 FF/ Wing veins more numerous. 



G. Finely netted wings. Neuroptera. 

 GG. Wings with fewer cross veins. Head 

 prolonged into a beak. Scorpion-flies, 

 etc. Mecoptera. 

 DD. Wings unequal in size. 



F. Wings entirely membranous. 



G. Front wings longer than the hind 

 wings. 



H. Wings finely netted. Abdomen 

 with long tail-like filaments. Eph- 

 emerida. 

 HH. Wings with fewer cross veins. 



I. Hind tarsi with two or three 

 segments. Psocids. Corrodentia. 

 II. Hind tarsi with four or five seg- 

 ments. Hymenoptera. 

 GG. Hind wings broader than front wings. 

 H. Wing veins with hair-like scales. 



Trichoptera. 

 HH. Wings without scales along veins. 



Hind wings folded. Plecoptera. 

 FF. Front wings leathery or hardened. 



G. Front wings leathery but flexible and 

 usually partially transparent . Orthoptera. 

 GG. Front wings hardened, seldom flexible. 

 Coleoptera. 



