THE CRAB-LOUSE 77 



than either of them, speaking of course of the 

 adults of each, its body being only about one- 

 fifteenth of an inch in length and one-thirtieth in 

 breadth, and while the body-louse is about three 

 times as long as broad, the crab-louse in length 

 measures rather less than twice its breadth. 

 Moreover, while the legs of the body-louse are 

 well separated and obviously adapted for balan- 



FIG. 13. CLAW OF THIRD LEG OF CRAB-LOUSE GRASPING PUBIC HAIR. 



cing the body in locomotion, those of this species 

 stick straight out, near together, awkwardly from 

 the body. The first pair of legs are slender, while 

 the other two pairs are correspondingly stout, 

 with very strong claws (Fig. 13), most remarkably 

 adapted for clinging on to hair. The inner edges 

 of the claws are strongly serrated, much more so 

 than in the case of the other human lice, and thus 

 they obtain a firmer hold upon the hair as the 



