16 



HIBERNATION OF THE COTTON BOLL WEEVIL. 



At Victoria, Tex., Large numbers of weevils were still active in 

 the fields about the middle of December, 1002, at which time direct 

 observations were discontinued. It is probable, however, that 

 weevils were gradually seeking winter quarters at any time after 

 the firsl of that month. Prof. E. I). Sanderson states that at College 

 Station, Tex., in 1903 weevils did not cuter hibernation until after a 

 freeze which occurred on November 18. After this date theysoon dis- 

 appeared. In 190.*), at Victoria, hibernation began between Novem- 

 ber L5 and 30. At several points between College Station and Terrell, 

 Tex., in 1904, hibernation began about November 10 and was not 

 complete until early in December. During this same year at Victoria 

 it occurred during the period from November 11 to about December 

 s. The following year at Victoria it did not occur until after Decem- 

 ber 15, while in 1906 at the same place weevils entered hibernation 

 between November 9 and 20. At Dallas, Tex., in 1905, few weevils 

 entered hibernation before the end of November, when heavy frosts 

 occurred, but they disappeared in the fields during the first few days 

 of December. At Dallas in 1906 weevils entered hibernation between 

 November 15 and December 1. 



These conclusions as to the approximate periods when weevils 

 entered hibernation are based upon field observations which showed 

 the gradual disappearance of the weevils from the plants. The con- 

 clusions from field observations are supported, also, by those from 

 cage experiments. 



PROPORTION OP EACH SEX AMONG WEEVILS IX FALL. 



Determinations of sex proportion among weevils in midsummer 

 have shown that during that period the sexes exist in approximately 

 equal numbers. As the development becomes retarded by approach- 

 ing cold weather there seems to be a tendency toward the production 

 of more males than females. The generally longer life of males may 

 also account in part for the increased proportion of that sex, which 

 is shown in the following table : 



Table I.— Proportion of male and ft male wet vils <it time of entering hibernation. 



year. 





Female. 



Number. 



Per cent. 



Number. 



Per .I'm. 



I'.Hil 



1905 



557 



(13 

 173 

 173 

 19 

 31 

 29 



r.7. 7 



317 

 1L'7 

 7s 

 IL'7 

 11 

 19 

 26 



36.3 

 12. 3 



1906 



1906 . 







1906 



.">7. 6 

 62.0 

 52. 7 



12. 1 



17.:; 



1904 



L906 





60.0 



708 



40.0 



