40 HIBERNATION OF THE COTTON BOLL WEEVIL. 



The beginning of this work occurred so hite in November that none 

 of the sections can be considered as having been phiced in hiberna- 

 tion early. Cold weather occurred between about November 30 and 

 December o, during which time the majority of weevils entered 

 hibernation. Emergence appears to have begun on IMarch 22, and 

 the last weevils emerged on June 28. The emergence during April 

 and May was quite uniform, while during June it decreased rather 

 steadily. In these records no allowance has been made for the escape 

 of weevils through the wire on the cage. Using the number placed 

 in the cage (25,800) as a basis, the 728 weevils which emerged con- 

 stitute a survival of 2.82 per cent. It is impossible to call attention 

 to all of the many interesting points shown in this table. Special 

 emphasis, however, will be given several points through the rear- 

 rangement of the significant data in succeeding tables. 



Since climatic conditions are primarily responsible for hiberna- 

 tion and the emergence of weevils therefrom, the records should 

 be studied in relation to a chart of the temperature conditions, 

 such as is given in figure 1. No climatic records are available for 

 Keatchie previous to the beginning of these observations upon March 

 15. The emergence of weevils may well be shown in relation to the 

 range in temperature upon the same chart. In studying the effects 

 of temperature variations upon weevil activity it has been found 

 that those temperatures which are about 43° F. alone produce activity 

 among the weevils. Because of this fact 43° F. is regarded as the 

 starting point in emergence records, and all temperatures above 43 

 degrees may be spoken of as "elTective temperatures" upon the 

 following diagram; the average between the maximum and minimum 

 extremes for the day is recorded as the mean average temperature. 

 While it is probably true that maximum temperatures have a special 

 significance in their effect upon emergence from hibernation, and that 

 minimum temperatures have a special effect upon entrance into 

 hibernation, it will be more simple and sufficient in this study to use 

 the single line representing mean average temperature during the 

 emergence period. 



From this diagram it will be seen that the emergence at Keatchie 

 in 1906 occurred practically during four rather clearly defined periods. 

 These periods are separated by marked declines in the mean average 

 temperature. It will be noticed that as it became warmer following 

 these cold ])eriods there was an increased emergence of the weevils. 

 After the middle of Ma}^ so large a proportion of the living weevils 

 had emerged that the number recorded became gradually smaller, 

 although the temperature rose still higher. 



Some of the special facts demanding attention are those relating 

 to the effect of the various conditions of shelter upon the survival 

 of weevils, the relation of emergence to effective temperature in 



