RECENT STUDIES OF THE MEXICAN COTTON BOLL WEEVIL. 17 



When the male and female weevils were placed together in the dry 

 tubes daily they very rarely failed to copulate. They would usually 

 unite within a few minutes after being being placed in the tube and 

 it was very rarely that they copulated at all if they did not start 

 almost immediately after having the opportunity. It was extremely 

 rare for the two sexes to remain together without copulation for a half 

 hour and then unite. 



The various breeding series in which one pair of weevils were 

 together on squares were examined only once daily and many pairs 

 were found in copula day after day when making these daily exam- 

 inations. In the field it was very noticeable that a pair usually 

 united as soon as they were placed together on a plant. When wee- 

 vils are collected in the field and placed in a tube it is the com- 

 mon occurrence for many pairs to unite as soon as dropped in the 

 tube. Hence it seems probable that it is normal for a single female 

 to be in copula many times and for the weevils to copulate almost 

 whenever they meet in the course of their travels over the plants. 



Three females deposited a total of 7 eggs externally. These eggs 

 were deposited during the days when the same females deposited 

 other eggs normally. As the females were certainly fertile, owing to 

 the almost daily copulations, this shows that external deposition 

 of eggs may be due to some cause other than infertility. The eggs 

 deposited externally by these females were tested for viability and 

 all hatched. 



Fecundity of A. grandis females after hibernating. — Twelve females 

 were collected in the field at Victoria, Tex., May 8 to 10, shortly after 

 emergence from hibernation, and fed on cotton leaves until squares 

 became available. Then each was placed with a male and given 

 fresh squares daily for oviposition. These females were all observed 

 until their normal death. The results secured are shown in Table 



VIII: 



Table VIII. — Fecundity of females of A. grandis after hibernating. 



Number of females. 



Total eggs 

 laid. 



Average 

 eggs per 

 female. 



Approxi- 

 mate ovi- 

 position 

 period per 

 female. 



Eggs per day. 



Average. 



Maximum. 



2 



144 

 673 

 302 

 336 

 715 

 701 

 100 



72 

 336.5 

 302 

 168 

 357.5 

 350.5 

 100 



Days. 

 12 

 32 

 53 

 25 

 55 

 46 

 13 



6.0 

 10.5 

 5.7 

 6.7 

 6.5 

 7.6 

 7.6 



14 



2 



1 20 



1... 



12 





11 



2 



12 



2 



19 



1 



11 







Total, 12 



2,971 





406 

 33.8 









247.6 











7.3 

 10.5 

 5.7 









358 

 72 



55 

 12 



20 







11 









1 The 2 females in this lot deposited 39 eggs in 1 day. Therefore one of them laid at least 20 eggs. 

 89032°— Bull. 231—15 3 



