HEXAPODA. 79 



EE. Body not compressed ; tarsi one-, two , or three-jointed. 



F. Last joint of tarsi bladder-like or hoof-like in form and 



without claws , mouth-parts forming a triangular, un- 



jointed beak; palpi present, p. 119 PHYSOPODA. 



FF. Last joint of tarsi not bladder-like, and furnished with 

 one or two claws ; mouth-parts forming a slender, usually 

 jointed beak; palpi apparently wanting, p. 121. 



HEMIPTERA 

 AA. Winged. (The wing-covers, elytra, of beetles and of earwigs 



are wings.) 

 B. With two wings. 



C. Wings horny, leathery, or parchment-like. 



D. Mouth-parts formed for sucking. Wings leathery, short- 

 ened, or membranous at the tip. p. 121 HEMIPTERA. 



DD. Mouth-parts formed for biting. Jaws distinct. 



E. Wings horny, without veins. Hind legs not litied tor 



jumping, p. 494 . . . . . . . . .CoLEOPTERA. 



EE. Wings parchment-like, with a network of veins. Hind 



legs fitted for jumping, p. 104 , . . .ORTHOPTERA. 



CC. Wings membranous. 



D. Abdomen with caudal filaments. Mouth-parts rudimentary. 



E. Halteres wanting, p. 86 EPHEMERIDA. 



EE. Halteres present (males of Coccidce). p. 121. HEMIPTERA. 



DD. Abdomen without caudal filaments. Halteres in place of 



second wings. Mouth-parts formed for sucking, p. 413. 



DIPTERA. 



BB. With four wings. 

 C. The two pairs of wings unlike in structure. 



D. Front wings leathery at base, and membranous at tip, often 

 overlapping. Mouth-parts formed for sucking, p. 121. 



HEMIPTERA. 

 DD. Front wings of same texture throughout. 



E. Front wings horny or leathery, being veinless wing- 

 covers. (Elytra) 

 F. Abdomen with caudal appendages in form of movable 



forceps, p. 102 EUPLEXOPTERA. 



FF. Abdomen without forcep-like appendages, p. 494. 



COLEOPTERA. 



EE. Front wings leathery or parchment-like, with a network 

 of veins. 



F. Under win^s not folded. Mouth-parts formed for suck- 

 ing, p. 121 HEMIPTERA. 



