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 



