siiki. I 1.1; DURING HIBERNATION. 25 



fell below 32 degrees <>nl\ once during this month. From December 

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

 this case tin" range of temperature varies from an absolute maximum 

 of 83 degrees to an absolute minim um of 32 degrees, the latter occur- 

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

 conditions were not sufficiently severe either to destroy absolutely 

 the food supply of the weevils or to insure the continued inactivity 

 of those which ni;i\ have sought shelter during the shod periods of 

 cool weather. Sprout cotton was exceptionally abundant throughout 

 the winter and \\ eevils were found feeding upon it almost continuously. 

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

 average temperature of 60 degrees is too high for 1 he complete hiberna- 

 tion of the weevil; that hibernation usually takes place coincidently 

 with tlu 4 decrease in mean average temperature to about 55degr< 

 and that it remains complete until the mean average temperature 

 subsequently rises to above 60 decrees. 



SHELTER DURING HIBERNATION. 



While many weevils seek hibernation shelter outside the field it 

 is certain that a considerable number of them remain very Dear 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 favorable 

 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 arc presented in the following two tables. Table VII 

 shows a comparison of the records for several localities during four 

 months of the winter of L904-5. 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 the season 

 advanced. 



