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TEXTBOOK OF ZOOLOGY 



Mallophaga, Dermaptera, Isoptera, and Orthoptera. The Lepidop- 

 tera, Diptera, Heteroptera, Homoptera, and Siphonaptera are suc- 

 torial orders. A knowledge of the mouth parts is very useful if 

 insects are to be effectively controlled and classified. No other 

 group of organs within the insect body vary in form as do the 



Fig. 174. — Mouth parts of Bhomaelia microptera. G, cardo ; Gl., clypeus • Ga., 

 galea; L, labium; La, labium (second maxilla); Lac, laclnia ; I/t., ligula ; L-i"; 

 labial palp; M., mandible; Me., mentum ; MP., maxillary palp; ilfa;. first maxilla; 

 Pa., palpifer; Sin., submentum ; /St., stipes. (From White, General Biology.) 



mouth parts. The mandibulate mouth parts are the type from 

 which the suctorial type has been evolved. In the mandibulate 

 mouth parts there is a labrum or upper lip which is attached on its 

 upper border to the clypeus and extends down over the mandibles. 

 The mandibles or jaws are true appendages which move in a trajis- 



