7 8 THE STUDY OF INSECTS. 



CC. Head not prolonged into a trunk. 



D. Louse-like insects of small size ; body less than one-sixth 

 inch in length. 

 E. Antennae with not more than five segments. (Bird-lice.) 



p. ioo Mallophaga. 



EE. Antennae with many segments. (Book-lice.) p. 98. 



CORRODENTIA. 



DD. Insects of various forms, but not louse-like, and, except 

 in the case of some ants, with the body more than one-sixth 

 inch in length. 



E. Abdomen with short, conical, compressed, many-jointed 

 caudal appendages. [Cockroaches.) p. 104...ORTHOPTERA. 

 EE. Abdomen without jointed caudal appendages. 



F. Legs fitted for jumping. {Wingless Locusts, Grasshop- 

 pers, and Crickets?) p. 104 ORTHOPTERA. 



FF. Legs fitted for running. 

 G. Abdomen broadly joined to thorax. 



H. Body linear. (Walking-sticks?) p. 104. 



Orthoptera. 

 HH. Body white and somewhat ant-like in form. 



( Termes.) p. 95 Isoptera. 



HHH. Body neither linear nor ant-like in form. 



( Wingless Fire- fly et al.) p. 494 COLEOPTERA. 



GG. Base of abdomen strongly constricted. {Ants et al.) 



p. 599 Hymenoptera. 



BBB. Mouth-parts formed for sucking. 



C. Small abnormal insects in which the body is either scale-like 

 or gall-like in form, or grub-like and clothed with wax. The 

 waxy covering may be in the form of powder, of large tufts or 

 plates, of a continuous layer, or of a thin scale, beneath which 



the insect lives. (Coccidce.) p. 121 Hemiptera. 



CC. Body more or less covered with minute scales, or with 

 thick long hairs. Prothorax not free {i.e., closely united with 

 the mesothorax). Mouth-parts usually consisting of a long 



" tongue " rolled beneath the head. p. 191 Lepidoptera. 



CCC. Body naked, or with isolated or bristle like hairs. 



D. Prothorax not well developed, inconspicuous or invisible 

 from above. Tarsi five-jointed. Mouth-parts developed 

 into an unjointed trunk ; palpi present, p. 413 ... . Diptera. 

 DD. Prothorax well developed. 



E. Body strongly compressed ; tarsi five-jointed. (Fleas.) 

 p. 490 , Siphonaptera. 



