SHELTER DURING HIBERNATION. 25 



fell below 32 degrees only once during this month. From December 

 1 to 21 the mean average temperature was also 60.4 degrees. In 

 this case the range of temperatiu-e varies from an absolute maximum 

 of S3 degrees to an absolute minimum of 32 degrees, the latter occitr- 

 ring only once. From these records it is apparent that the climatic 

 conditions were not sufRciently severe either to destroy absolutely 

 the food supply of the weevils or to insiu-e the continued inactivity 

 of those which may have sought shelter during the short periods of 

 cool weather. Sprout cotton was exceptionally abundant throughout 

 the winter and weevils were found feeding upon it almost continuously. 

 From these facts we may be justified in concluding that a mean 

 average temperature of 60 degrees is too high for the complete hiberna- 

 tion of the weevil ; that hibernation usually takes place coincidently 

 with the decrease in mean average temperature to about 55 degrees ; 

 and that it remains complete until the mean average temperatm-e 

 subsequently rises to above 60 degrees. 



SHELTER DURING HIBERNATION. 



Wliile many weevils seek hibernation shelter outside the field it 

 is certain that a considerable number of them remain very near their 

 food supply — that is, in the cotton fields and in the immediate 

 vicinity. Because of the differences in the nature of the weevil shelter 

 and in the possibility of destroying or removing such faA^orable 

 shelter, within and without the cotton fields, these two conditions 

 will be considered separately. 



SHELTER IN BOLLS. 



Within the cotton fields weevils are sheltered primarily in the 

 hanging cotton bolls, the fallen foliage, and grass or other rubbish 

 which may have accumulated upon the surface of the ground. 

 Attention has already been called to the fact that many stages enter 

 the period of hibernation in an immature condition in unopened 

 bolls. (See p. 14.) That many adult weevils hibernate entirely 

 within the protection afforded by the bracts and hulls of bolls has 

 been abundantly demonstrated (PI. II, fig. 3). Rather extensive 

 experiments have been made upon this point in a number of localities 

 during several seasons. The principal data resulting from these 

 investigations are presented in the following two tables. Table VII 

 shows a comparison of the records for several localities during four 

 months of the winter of 1904-5. During this period the prevailing 

 climatic conditions were the most severe that the weevil has en- 

 countered since invading Texas. The table shows therefore a 

 gradual decrease in the number of living stages present as th§ season 

 advanced. 



