94 ECONOMIC ENTOMOLOGY 



AA. With four wings. 



B. Mouth-parts formed for biting. 



C. Upper wings horny; metamorphosis complete. — COLEOPj'^j^ji 

 (Beetles), p. 280. 

 CC. Upper wings parchment-like; lower wings folded under the 

 upper; metamorphosis incomplete. — ORTHOPTeROIDA 

 Group (Locusts, etc.), p. 102. 

 CCC. Upper wings membranous with many veins. — NEUROP- 

 TEROIDA Group (Nerve-winged insects), p. 96. 

 BB. Mouth-parts formed for sucking and biting; wings with few cross veins 

 and similar in texture; metamorphosis complete. — HYMENOP- 

 TERA (Bees, etc.), p. 343. 

 BBB. Mouth-parts formed for sucking; wings covered with scales; metamor- 

 phosis cora^\tie.—LEPI DOPTERA (Butterflies and moths), p. 169. 

 BBBB. Mouth-parts formed for piercing. 



C. Beak jointed; palpi absent; last joint of tarsi not bladder-like. 

 D. Wings of uniform texture; beak arising from the hinder 

 edge of under side of the head; metamorphosis incomplete. 

 —HOMOPTERA, p. 122. 

 DD. Fore wings leathery at base, membranous at tip; beak 

 arising from the front of the head; metamorphosis incom- 

 plete.— Z^£M/Pr£i?J (True Bugs), p. 158. 

 CC. Beak unjoin ted, palpi present; last joint of tarsi bladder-like, 

 and without claws; wings similar; metamorphosis incomplete. — 

 THYSANOPTERA (Thrips), p. 118. 

 AAA. Wingless. 



B. Mouth-parts formed for biting; louse-like insects. 



C. Mouth-parts retracted within the head; no metamorphosis. — 

 APTERA Group, p. 94. 

 CC. Mouth-parts not retracted within the head. 



D. Antennas with many segments; metamorphosis incomplete. 

 —CORRODENTIA (Book-lice), p. 103. 

 DD. Antennas with not more than five segments; metamorpho- 

 sis incomplete. — MALLOPHAGA (Biting-lice), p. 100. 

 BB. Mouth-parts formed for sucking. 



C. Tarsus with a single hook-like claw; with a fleshy unjointed 

 beak; parasitic on mammals (Parasitica). — SIPHUNCULATA, 

 p. 167 

 CC. Tarsus five-jointed; body compressed; metamorphosis complete. — 

 SIPHONAPTERA (Fleas). 



The Aptera Group 

 Chief Orders and Families: 



A. Abdomen with at least 10 segments; antennae many-jointed; usually with 

 terminal abdominal appendages. — Thysanura Order. 

 B. Body covered with scales. — Lepismidce. 



