100 THE CRAB-LOUSE. 
THE CRAB-LOUSE. 
(Phthirius inguinalis or pubis Leach). 
This parasitic insect belongs to a different genus of lice, 
as can be seen by its heart-shaped form and broad thorax, 
which is not separated from the abdomen (fig. 68). The 
former is composed of two segments soldered together, the 
latter of eight flat joints. The first pair of legs are feeler- 
like and possess slender tarsi; the claws of the two other 
pairs are large and strong, with a moveable thorn, toenable 
the insect to secure a strong hold upon the hairs. Thehead, 
broad in front, carries five-jointed feelers, and behind them, 
upon two projections, the two simple eyes. The end of the 
abdomen in the male is rounded, that of the female is bi- 
lobed. Owing to the peculiar shape, the strong legs spread- 
ing out laterally, this louse resembles a minute crab, hence 
the name ‘“‘crab-louse.”’ It is of a whitish color, with a 
dusky ill-defined spot upon each shoulder; the legs are red- 

Fig. 69.—Crab-louse of 
Fig. 68.—Crab-louse of man. Greatly enlarged. man, egg. Greatly en- 
Original. larged. Original. 
dish, with darker claws. The male measures 1mm. in 
length, the female 1.2mm. The pear-shaped eggs (fig. 69), 
0.9mm. long and 0.5mm. wide, are glued at their pointed 
ends to hairs; about ten eggs are deposited. 
This species lives among the hairs of the pubic regions of 
man, and, also, though not very frequently, upon the breast, 
arm-pits, even in the beard, eye-brows and on the head. As 
these nasty parasites cling frequently to linen and other 
