78 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 M ALLOPHAGA. 



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. 



( Whig less 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 c r 

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



the insect lives. (Coccida.) 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. 49° Siphon aptera. 



