RECENT STUDIES OF THE MEXICAN COTTON BOLL WEEVIL. 7 



The maximum record of longevity made in the 1913 work is based 

 on a specimen of Anthonomus grandis thurberise, extracted from its 

 hibernation cell August 27, after at least nine months in hibernation, 

 which was still alive when the food supplies at Victoria gave out, 

 October 29. This gives the maximum known period of hibernation 

 as 270 days, and a total of over 333 days longevity. The maximum 

 recorded length of life is 335 days for a hibernated weevil at Tallulah, 

 La., in 1910. 1 



The maximum length of life of weevils after emergence from 

 hibernation was 73 days for males and 71 days for females, both of 

 which records are far below the highest previous records. 



A true comparison of females fed on blooms of Hibiscus syriacus 

 gives the average longevity of Arizona A. g. thurberix as 22.5 days, 

 Texas A. grandis as 16 days, and Louisiana A. grandis as over 27 

 days. 



The grandis males averaged 3.47 days on water, 5 days on Sphxral- 

 cea lindheimeri, 7.6 days on Cdttirrhoe pedata, 17.5 days on Hibiscus 

 syriacus, 20 days on Cdttirrhoe involucrata, and 33.2 days on cotton, 

 while the thurberise males averaged 27.6 days on Hibiscus syriacus. 



The grandis females averaged 3.32 days on water, 5.4 days on both 

 Sphseralcea lindheimeri and Cdttirrhoe pedata, 19.2 days on Hibiscus 

 syriacus, and 34.3 days on cotton, while the thurberise females averaged 

 25.5 days on Hibiscus syriacus. 



The greater longevity of weevils on the same food later in the 

 season is very evident and is due to the advance of hibernation 

 temperatures. 



Although the records of life on cotton were shorter than those 

 previously obtained when the totals are considered, it is noted that 

 they agree quite well for any given season. It is evident that tem- 

 perature and humidity exercise considerable control upon the length 

 of life on any given food. The average longevity on cotton leaves 

 was 11.9 days, on bolls 17.2 days, and on squares 42.1 days. 



Adding these new records to those previously obtained 5,858 

 weevils fed on water only averaged 10.1 days; 16 weevils fed on cot- 

 ton leaves only averaged 11.9 days; 226 weevils fed on miscellaneous 

 malvaceous plants averaged 13.2 days; 92 weevils fed on cotton 

 bolls averaged 19.9 days; 4,353 weevils fed on cotton foliage aver- 

 aged 24.5 days; and 147 weevils fed on cotton squares averaged 59.5 

 days. 



Comparing the sexes irrespective of food in all experiments hitherto 

 conducted 4,226 males averaged 17.7 days, and 3,624 females 

 averaged 18.5 days. 



1 The longevity records of 1913 have been greatly exceeded during 1914 in experiments conducted at 

 Washington, D. C. Weevils have been kept in a dormant state for over a year, and give promise of living 

 considerably longer. 



