648 Laura Florence 



Neither feces nor blood was ejected from the anus, but a drop of hyaline 

 fluid escaped from the sexual orifice almost simultaneously with the pointed 

 end of an egg. After a few seconds the louse moved awaj'', leaving the 

 egg attached to a hair on the arm. The position of the gonopods could 

 not be seen, but the posterior lobes of the ninth abdominal segment 

 surrounded the hair on which the egg was laid. According to Sikora 

 (1915:536), who has described the act of egg-laying on a bristle by a hog 

 louse in captivity in a vial, the insect remained motionless for almost 

 ten minutes after the first appearance of the egg, and then moved off 

 leaving the egg attached to the bristle. Watts (1918:9) says, "The entire 

 operation requires but a few seconds, so that one seldom sees a female 

 la}'' an egg unless watching closely for some time." In the ovaries the 

 eggs are oriented according to Hallez' law, and, when laid, the ventral 

 surface is attached to the bristle. The cement surrounds the bristle 

 but does not appear to surround the egg, which is attached to the bristle 

 between its transverse median line and its posterior end. One or more 

 eggs may be laid on the same bristle, not always pointing in the same 

 direction. After attachment we have always found them immovable, 

 but Watts (1918:9) states that he has found they can be slipped along 

 the hairs and are often pulled away from the body by the rubbing of the 

 animal. This, however, does not agree with his earlier statement on the 

 same page, that " each egg is glued to the base of a hair and is laid so 

 that the smaller end practicalljr touches the skin of the host, wliich keeps 

 the egg warm until it hatches, several daj^s later "; and, since the diameter 

 of the bristle diminishes toward the tip, the cement ring large enough to 

 surround the base of the bristle would tend to slip off, carrj'ing the egg with 

 it, thus causing an excessive mortality not provided for bj' overproduction. 

 In captivity the eggs are laid on bristles or threads of gauze, and the 

 number laid daily appears to depend on the opportunity to feed, as the 

 following table shows: 



Opportunities of Number of egg3 , ., ., 



feeding in 24 liours laid in 24 liours Aumority 



Four 2 Sikora 



Continuous 4 Sikora 



Continuous for 7 days 3 Claassen' 



Two 1-2 Florence 



' Unpublished data kindly communicated to the writer by Professor P. W. Claassen, of the Department 

 of Entomology, Cornell University. 



