56 HIBERNATION OP THE COTTON BOLL WEEVIL. 



(4) To determine the effect which different depths and classes of 

 shelter might exert upon the success of hibernation and also upon the 

 time of emergence and the range of the emergence period. 



(5) To test the power of adaptation whicli the weevils might have 

 acquired to varying climatic conditions by bringing weevils from 

 widely separated localities for comparison with weevils collected at 

 Dallas. In each test similar conditions of food and shelter should 

 exist in each locality. 



(6) To determine upon a large scale, in very widely separated 

 localities, the proportion of weevils entering hibernation which might 

 survive. 



(7) To determine the relation between climatic conditions and the 

 emergence period in each locality. To provide suitable and reliable 

 data for this study, standard Weather Bureau instruments were 

 secured and temperature, humidity, rainfall, and other records were 

 kept in each locality throughout the period covered by the experi- 

 ments. 



(8) To determine the longevity of hibernated weevils, especially 

 after emergence. Since all weevils used in this work were collected 

 promiscuously in the field immediately preceding their confinement 

 in the cages, all figures showing their longevity must be based either 

 upon the date when they were placed in hibernation or upon the date 

 of their emergence. In the latter case it would be distinguished as 

 longevity after emergence. 



It was planned to use from 2,500 to 3,000 weevils in each section 

 of the cages, although difficulties in the collection of the desired 

 number for the particular dates when experiments were to be started 

 occasionally caused some variation in this number. Adult weevils 

 only were used in sections 1 to 9, inclusive, in each cage, while in sec- 

 tion 10 the hibernation of weevils in bolls was tested. One-half of 

 the bolls were buried under 2 inches of dirt. The other half were 

 exposed upon the surface of the ground. (PI. X, fig. 1.) 



It is generally understood that the principal factor producing a 

 hibernation period is the lower temperature occurring during the fall 

 and winter months. In its effect upon the survival during this period 

 moisture is also an important factor. As a rule, in studies of these 

 factors investigators have been obliged to rely upon the climatic 

 reports published by the United States Weather Bureau for the par- 

 ticular locations desired. It happens frequently, however, that 

 there may be no report from the Weather Bureau for- the particular 

 locality desired. Both temperature and rainfall are liable to con- 

 siderable variation within comparatively short distances. In order 

 that the data for these studies of the hibernation of the boll weevil 

 might be complete and thoroughly reliable, we have kept full climatic 

 records in the immediate vicinity where experiments and cage obser- 



