HIBERNATION. 103 



ACTIVITY DURING THE HIBERNATION PERIOD. 



It is natural to expect that during warm periods of winter the tem- 

 perature will rise to a point which forces the weevils into activity., 

 Of course, the weevils under the lightest shelter are the ones which 

 first become active. It is these warm periods which cause the inter- 

 mittent development of the immature stages in dry bolls left in the 

 fields. In some winters the hibernation is incomplete throughout 

 the cotton belt, and in the extreme South it is probably so almost 

 every winter. This same temperature condition is responsible for 

 the growth of sprout cotton, which affords food in the warm periods. 

 Observations were made in January, 1907, on weevils feeding on 

 sprout cotton at Victoria, Tex., at a mean temperature of 67° F. 



DURATION OF HIBERNATION PERIOD. 



AVERAGE LENGTH OF HIBERNATION PERIOD. 



Many factors must be considered in arriving at the average length 

 of the hibernation period. The time of entrance, condition of the 

 weevils on entering, temperature and humidity before and during 

 hibernation, and nature of shelter, all have a decided effect upon the 

 duration of hibernation. In a series of condensed summaries we 

 have attempted to show how some of these factors act. 



In Table XXXVIII is to be found a general summary of the nine 

 large experiments conducted, with the extreme variations in each 

 series. From this table it appears that in the years 1906 to 1911 the 

 hibernation period has ranged between 62 and 255 days, and that in 

 1909 the range fell short only 1 day of this maximum range. It 

 also appears that the average duration in Texas is 26 days shorter 

 than in Louisiana. The period of emergence extends from Feb- 

 ruary 15 to July 1. 



Table XXXVIII.— Extremes of variation in duration of hibernation by the boll weevil. 



Place. 



Total 

 number 

 weevils 

 emerged. 



Total 



number 



weevil 



days. 



Mini- 

 mum 

 period. 



Maxi- 

 mum 

 period. 



Mini- 

 mum 

 aver- 

 age. 



Maxi- 

 mum 

 aver- 

 age. 



Aver- 

 age of 

 aver- 

 ages. 



Earliest 

 emergence. 



Latest 

 emer- 

 gence. 



Keatchie, La., 1906 



Mansura, La. , 1909 



Mansura, La. , 1910 



Tallulah, La. , 1910 



Tallulah, La., 1911 



731 

 3,260 

 1,038 



317 

 46 



114, 192 



516, 067 



170, 212 



58, 245 



6,587 



Days. 

 108 

 62 

 86 

 103 

 107 



Days. 

 222 

 254 

 232 

 237 

 231 



Days. 

 136 

 94 

 114 

 126 

 118 



Days. 

 178 

 199 

 217 

 224 

 158 



Days. 

 156 

 156 

 164 

 183 

 143 



March 22 



February 21. 

 February 15. 

 February 15. 

 February 15. 



February 15. 



February 28. 



March 4 



March 1 



March 2 



February 28. 



February 15. 



June 28. 

 June 29. 

 June 15. 

 June 27. 

 June 4. 



Louisiana aver- 

 age 



5,392 



865,303 



62 



254 



94 



224 



160 



June 29. 







Victoria, Tex., 1907.... 



Calvert, Tex., 1907 



Dallas, Tex., 1907 



Dallas, Tex., 1908 



3,028 



1,842 



3,462 



118 



383,797 



255, 831 



481, 271 



17, 839 



92 

 91 

 85 

 113 



223 

 255 

 233 

 217 



95 

 100 



98 

 121 



146 

 195 

 168 

 170 



126 

 138 

 138 

 151 



June 15. 

 July 1. 

 June 19. 

 June 16. 



Texas average . . . 



8,450 



1, 138, 738 



91 



255 



98 



195 



134 



July 1. 



Grand total 



13,842 



2,004,041 



62 



255 



94 



224 



144 



July 1. 



