396 



LICE 



form a little pus, sufficient in very negligent individuals (o make 

 the hair mat together. According to Stiles, il this is allowed to 

 run on, a regular carapace may I'orm, called iridiovia, in which 

 fungous growths may develop, and under which the lice abound, 

 and the head may exude a fcetid odor. 



Crab Louse. — The crab louse, Phthirius pubis (Fig. 176),' is 

 quite distinct from the other two species of human lice. It has 

 a very broad short body with long, clawed legs, presenting the 

 general appearance of a tiny crab, from which it derives its name. 

 The first pair of legs are smaller than the others and do not 



Fio. 170. Crub louse, Phthirius pubis, ? . X 36. 



possess a " thumb " in apposition to the curved claw. The 

 abdomen is composed of six segments, and is niari<edly festooned 

 along the sides. This louse is grayish whiti^ in color, with dark 

 shoulder patches and slightly reddish legs. The females are 

 about iV of an inch in length, the males somewhat smaller. The 

 favorite haunts iivi; the pubic regions and olliei' parts of the body 

 where coarse hair grows, as in thc^ armpits and in the beard and 

 eyebrows. Unlike the other human lice; this species is almost 

 exclusively confined to the (Caucasian race. 



The females producn^ from ten to 15 eggs and glue them, one 

 at a time, fo the coarse hairs among which they live. A number 



