SOME WINGLESS INSECTS 



161 



Such cases, though relatively few, are not rare among beetles, 

 moths and two-winged flies, and the well-known parasitic group 

 of the Fleas 1 afford an example of an entire order (the 



FIG. 92. 



, Dog-flea (Ctenocephalus canis), male (side view), xiz. b, feeler, x 200. 

 c, jaws; d, labium. x 50. e, egg; /, larva, (side view), xiz. g, head of 

 larva; h, tail-region, xaoo. j, cocoon; k, pupa, x 12. From Howard. 

 U.S. Dept. Agric. 



Aphaniptera) of metamorphic insects with wings absent or 

 reduced to the merest vestiges. The general aspect of an ordin- 

 ary flea (Fig. 92 a) with its body strongly compressed from side 



1 H. Russell : " The Flea ". Cambridge, 1913. F. C. Bishopp : 

 " Fleas ". U.S. Dept. Agri. Bull. 248. 1915. 



II 



