IMPORTANT INSECT ENEMIES OF COTTON 129 



emerged individual is light yellowish in color, changing 

 to a gray or nearly black shade as it becomes older. It 

 is about one-fourth of an inch in length, including the 

 snout which is about one-half the length of the body 

 (Fig. 19). The breadth of the weevil is about one-third 

 of its length. 



150. Food of the weevil. So far as is known at 

 present, the cotton boll-weevil has no food plant other 

 than cotton. It has been erroneously reported as feeding 

 upon peas and various other plants. Such reports are in 

 all probability due to the confusion of the boll-weevil 

 with other weevils of quite similar appearance. The 

 fact that the boll-weevil feeds on no plant other than cot- 

 ton is made the basis of important measures of control. 



161. Rate of increase. The time required for a 

 boll-weevil to develop from an egg to an adult depends 

 upon weather conditions, especially as regards tempera- 

 ture. Under average conditions from two to three weeks are 

 required. The first eggs are laid as soon as the first squares 

 appear in the spring and their rapid multiplication contin- 

 ues until checked by frost. W. D. Hunter of the Bureau 

 of Entomology, Washington, D. C., states that "a con- 

 servative estimate of the possible progeny of a single pair 

 of weevils during a season beginning on June 20th, and 

 extending to November 4th is 12,755,100." That this 

 estimate is very conservative is shown by the fact that 

 Hunter allowed for only four generations in a season, and 

 for each female's laying only 100 eggs. Investigations 

 seem to indicate that the average number of eggs laid by 

 each female is approximately 140. 



152. Dissemination. The boll-weevil moves from 

 one locality to another by making successive short flights. 

 It is little inclined to fly, however, except during the period 



