70 AN ECONOMIC ENTOMOLOGY. 



contains insects that simulate injurious forms, while doing little 

 or no actual damage themselves. 



Family mallophagid^. 



The literal meaning of this term is ' ' wool eater, ' ' and it ap- 

 propriately expresses the habits of some of the species. All 

 members of this family are parasitic, and are known as biting 

 lice ; never sucking blood, but feeding upon young hair, feathers, 

 skin-scales, clots of blood, and scabby or other scurfy material 

 found on the skin or among hair and feathers. They infest 

 warm-blooded animals only, and principally birds, whence the 

 term ' ' bird-lice' ' has been erroneously applied to the entire 

 group. All the common farm animals except the pig are infested 



Fig. 38. 



Biting-lice.— a, dog-louse, Trichodectus latus ; b, sheep-louse, Tm'ckodectus sphcero- 

 cephalus ; turkey-louse, Go?iiodes stylifer. 



by some species of this family, and all the poultry or fowls are 

 troubled to a greater or less extent. 



The insects are all small, flattened, with large, prominent head, 

 often bulging eyes, and short antennae or feelers. The legs are 

 short and stout, fitted for holding to and moving among hair or 

 feathers, and the abdomen is oval. No trace of wings is ever 

 developed. 



The eggs are fastened to the hair or feathers of the host, and 

 in a few days the young emerge, not differing from their parents 

 except in size and sexual immaturity. The entire life is thus 



