46 



INSECT ENEMIES OF THE BOLL. WEEVIL. 



pointed out that these mites reproduce viviparously and that their 

 offsprmg are mature and fertile at birth. He found that when they 

 attach themselves to a host the abdomen commences to inflate 

 until it becomes many times larger than the thorax. The time 

 required for engorgement varies from 2 to 5 days. Wlien the abdo- 

 men commences to grow, the young commence to leave the parent. 

 The males fertilize the females before leaving the parent's body and 

 shortly afterwards die. An average of 100 female offspring to an 

 individual was recorded. Rangel found that in 48 hours, 21 stages 

 out of 40 in squares were attacked by the mites. In larger series of 

 tests, after four days 50 out of 153 weevil stages in squares were 

 attacked, or 32.6 per cent. 



a 



Fig. 8.—Pediculoides ventricosus: a, Adult female before inflation of abdomen with eggs and young; 

 6, adult female after inflation of abdomen with eggs and young. Greatly enlarged. (Redrawn from 

 Brucker.) 



Pediculoides n. sp. This mite was discovered in the laboratory at 

 Dallas, Tex., June 13, 1907, by the senior author. Careful observa- 

 tions on the length of generations were made with the following 

 results: A gravid female was isolated June 13 and on June 17 there 

 were 31 gravid mites. All but 5 were removed. On June 19 there 

 were many offspring, one mite being well grown. On June 21 the 

 fourth generation began to appear. In other words, between June 

 13 and June 21, that is, in less than 8 days, there were two com- 

 plete generations. Another genealogy was as follows : Parent isolated 

 June 13, second generation began to appear June 14, were mature 



