28 



HIBERNATION OF THE COTTON BOLL WEEVIL. 



Wliile these records show that few if any weevils survived in the 

 shelter of bolls during this season it must be remembered that the 

 weevils were not exterminated in all of these localities. Other con- 

 ditions of shelter were evidently so much more favorable than bolls 

 as to have enabled the weevils to survive this severe winter. It is 

 true, however, that in the spring of 1905 weevils occurred in much 

 smaller numbers than is usually the case. 



Other examinations of bolls show that in the northern portion of 

 the infested area of Texas there is a smaller percentage of Hving stages 

 in the bolls than in the southern portion. The data for three seasons 

 are compared in Table IX. The periods selected are during the 

 last of the winter season in each year. 



Table IX. — Increase in percentage of survival in bolls from northern to soutliern Texas. 



It is noticeable that there is a gradual increase in the living stages 

 from north to south, and that toward the end of the hibernation period 

 nearly all of the living stages are adults, most of which had matured 

 before the beginning of hibernation. 



That the increased mortality found in bolls during the winter of 

 1904-5 can not be attributed entirely to the exceptional severity of 

 that season is shown by the fact that a similar decrease in the per- 



