The Hog Lotjse 647 



have gorged themselves and have been seen to turn pink within a few 

 minutes, owing to the rupture of the stomach and the spread of blood 

 through the colon. This phenomenon, which has been invariably followed 

 by death, has been seen also by Nuttall (1917 d: 173) in the pediculi 

 infesting man. The unfed louse is of a grayish color and much MTinkled, 

 while the fed louse has a highly refractive, smooth tegument showing 

 very clearly the areas of stronger chitinization. During keeping and 

 rearing, immature lice have been given four, and adult lice three, oppor- 

 tunities for feeding in twenty-four hours, and these were not always 

 taken advantage of. Temperature influences the rate of digestion, and 

 the higher the temperature in which lice are kept, the more frequent must 

 be the opportunities given them for feeding. 



Sexual maturity is attained on the third day after the final molt, when, 

 with or without fecundation, egg-laying begins. The position for copu- 

 lation has been observed a number of times. While a female was feeding 

 and still had the abdomen somewhat elevated, the male crawled under- 

 neath and interlocked his flrst and second pairs of legs with the second 

 and third pairs of the female. She at once raised her abdomen, resting 

 only on the head and the first pair of legs and bearing the whole weight 

 of the male. The abdomens of both were curved dorsad and the male 

 was seen to insert the parameres (dilator of Nuttall) into the sexual 

 orifice of the female. Gradually the bodies were lowered until the third 

 pair of legs of the male rested on the arm, and the head was under that 

 of the female. They remained in this position for almost ten minutes, 

 during which time the male constantly stroked the head of the female 

 with his antennae. In its main features this resembles copulation in the 

 pediculi infesting man as described by several workers, the most detailed 

 account being that of Nuttall (1917 a; 316). Hog hce in captivity have 

 not been seen to remain in copulation longer than from ten to fifteen 

 minutes, while the species infesting man crawl into hiding and remain so 

 for several hours. 



The eggs (Plate LVIII, 2) are laid, one at a time, on the bristles of the 

 hog and are attached to them by a clear cement. They are most abundant 

 on the lower parts of the body. The egg-laying process has been watched 

 on the human arm during feeding. After drawing blood for almost ten 

 minutes, the female withdrew the mouth parts but remained stationary, 

 holding the end of the abdomen bent downward in an unusual manner. 



