84 



EIBERNATION OF THE COTTON BOLL WEEVIL. 



LONGEVITY OF I M'KD WEEVILS AC lilt EMERGENCE FROM HIBERNATION. 



Since the duration of life of unfed weevils was so ruuch shorter 

 than for fed weevils, the records of the former will be considered 

 first. The principal object in the experiments with unfed weevils 

 was to determine the time which thev might survive while waiting 

 for the growth of a food supply in the spring. The results have a 

 most important special bearing upon the advisability of hastening 

 or deferring the time of planting of cotton, especially when considered 

 in connection with the period of emergence from hibernation. The 

 figures given are based upon completed records only, all partial 

 records having been discarded. 



Table XLIII. — Longevity of unfed weevils after emergence from hibernation, March 



to Jul,/. 1907. 





Number 



of series 



unfed. 



Total 



weevils 



emerged. 



Weevils in series lots. 



Maximum life. 



ge duration of life. 



Locality. 



Total. 



d" 



9 



S 



9 



cf 



9 



Hot!) 

 sexes. 



Texas: 



Calvert 



Dallas 



Victoria 



25 



19 



17 



1,085 

 2,317 

 1,418 



1,079 

 2,179 

 1,360 



585 



1,178 

 875 



494 



1,009 



485 



Days. 

 48 

 90 

 44 



Days. 



'26 

 88 

 40 



Days. 

 8.05 

 13.00 

 8.00 



Days. 



8.09 



11.09 



7.40 



Days. 

 8.07 

 12.50 

 8.20 



Total and 

 average . 



61 



4,820 



4,618 



2,638 



1,9S8 90 



88 



10.30 



9.80 10.10 



The records both for maximum and average duration of life are very 

 important. In the record showing maximum and average duration 

 of life for each sex in each locality the time at Dallas exceeds by 50 

 per cent the time at either Calvert or Victoria. It should be stated 

 that when weevils are kept in confinement it is probable that the most 

 favorable conditions which can be furnished them can hardly be sup- 

 posed to prolong their life beyond the normal condition in the field.. 

 Any unfavorable conditions in the cages will shorten the period. It 

 was found in the course of the work that whenever sunshine was 

 allowed to strike directly on the lantern globe breeding jars in which 

 the weevils were for the most part confined, the heat and excessive 

 humidity generated within the globe caused an abnormal activity 

 among the weevils, and if prolonged or frequently repeated, it 

 result c(l in their early death. It was also found that in the breeding 

 ca^es among the unfed weevils the degree of moisture was less than 

 would normally occur on plants or at the surface of the ground in the 

 field. This dryness also naturally shortens the life of weevils. In 

 an experiment at Dallas series 14 was kept with plenty of moisture 

 while series 15 was div. Otherwise conditions in the two series were 

 identical. The average life in the wet series was 20.:; days while in 

 the dry series it was but 7.1 days. Other experiments pointed to the 

 same conclusion. 



