72 



HIBERNATION OF THE COTTON BOLL WEEVIL. 



unusually unfavorable, but in all sections it ranged from 3 to 5 

 degrees below the normal. This decrease was not, however, sufficient 

 to check the emergence of weevils, although undoubtedly it served to 

 extend the period of emergence in an unusual degree. The abnormal 

 nature of the temperature conditions for the spring of 1907 may be 

 understood from a comparison of the mean monthly temperatures for 

 these four months in each case. The normal is determined by the 

 Weather Bureau records from an average of the mean monthly tem- 

 peratures for the entire period during which records are available. 

 The departure of each season, therefore, affects the normal for the 

 following season. 



The general impression in regard to the exceptionally high tem- 

 perature experienced during the winter of 1906-7 is confirmed by a 

 comparison with the average records for a number of seasons. Tem- 

 perature alone need be considered in making this comparison, although 

 rainfall has an important direct effect upon temperature conditions. 

 For the following comparison the records given by the United States 

 Weather Bureau are used. As there is no report for Calvert the 

 average of two points about equally distant on opposite sides of that 

 place is used. 



Table XXXIV. — Mean monthly temperatures and departures from normal at Dallas, 

 Calvert, and Victoria, Tex., November, 1906, to February, 1907. 



It will be noted that the departure from normal during November 

 was very slight. The temperature conditions, therefore, during the 

 usual period of entrance into hibernation were practically normal, the 

 rise occurring during December and January, especially when weevils 

 should normally have been in complete hibernation. Table XXXV 

 continues the same study throughout the period of emergence from 

 hibernation. 



Table XXXV. — Mean average temperatures and departures from normal at Dallas, 

 Calvert, and Victoria, Tex., March to June, 1907. 



