BULLETIN 358, TJ. S. DEPARTMENT OF AGRICULTURE. 



Table I. — Duration of life of boll weevils. Observations of 1913-14. 



VABIETY GRANDIS "WITHOUT NORMAL FOOD. 



Season and period. 



Food. 



No. of 

 weevils. 



Weevil 

 days. 



Aver- 

 age 

 lon- 

 gevity. 



Maxi- 

 mum 

 lon- 

 gevity. 



Remarks. 



1913. 



Sept. 24 to Oct? 



Sept. 24 to Oct. 10... 

 Do 



Hibiscus leaves. . 

 Hibiscus bolls. . . 

 Hibiscus leaves, 



flowers, and 



bolls. 

 Okra buds and 



fruit. 



Okra fruit 



Okra leaves 



Thurberia leaves 

 Thurberia tips 



and buds. 

 Thurberia 



squares. 



4 

 4 

 4 



8 



8 

 4 

 4 

 4 



4 



24 

 25 



46 



44 



75 

 26 

 42 

 34 



29 



Dai)s. 

 6.0 

 6.3 

 11.5 



5.5 



9.4 

 6.5 

 10. 5 

 8.5 



7.3 



Days. 

 13 

 16 



16 



15 



18. 

 14 

 16 

 10 



14 



In paper bags on plants. 

 Do. 

 Do. 



Sept. 24 to Oct. 9.... 



Sept. 24 to Oct. 12. . . 

 Sept. 24 to Oct. 8.... 

 Sept. 24 to Oct. 10... 

 Sept. 24 to Oct. 4.... 



Sept. 24 to Oct. 8.... 



Do. 



Do. 

 Do. 

 Do. 



Do. 



Do. 



Total longevity on m 



alvaceous plants.. 



44 



345 



7.8 



18 





VARIETY GRANDIS WITH NORMAL FOOD. 



1914. 



Aug. 6 to — 



July 15 to Aug. 1.. 

 June 3 to Oct. 28.. 

 June 13 to Oct. 28. 



Cotton leaves 



Cotton bolls 



Cotton squares.. 

 do 



Total on normal food. 



40 



390 



9.8 



17 



20 



210 



10.5 



16 



24 



1,106 



46 



107 



24 



1,118 



46.6 



100 



108 



1 



2,824 



26.1 



107 



In glass tumblers. 



Do. 

 Females in glass tumblers. 

 Males in glass tumblers. 



Iii the abnormal food studies the weevils lived an average of 6 

 days on Hibiscus leaves; 11.5 days on Hibiscus leaves, flowers, and 

 fruit; 6.25 days on Hibiscus tips; 6.5 days on okra leaves; 9.4 days 

 on okra fruit: 11 days on okra leaves, flowers, and fruit; 10.5 days 

 on Thurberia leaves; 8.5 days on Thurberia tips and buds, and 7.3 

 days on Thurberia squares. These records are all low, probably due 

 to the experimental methods, as the w T eevils w r ere all placed upon the 

 food in paper bags and later observations show that the method 

 apparently causes an early death. 



SEASON OF 1915. 



The studies of 1915 compare the longevity of grandis weevils on 

 moist sand with no food, on moist sand with okra and Hibiscus, on 

 moist sand with different parts of the cotton, and also ihurberiae, on 

 moist sand with okra, with cotton bolls, and with cotton squares. 

 The species of Hibiscus used were H. militaris and H. moscheutos. 

 The results are given in Table II. 



