SEASONAL HISTORY. 



49 



On sweetened water 12 weevils lived an average of a little less than 

 6 days. Six weevils fed upon molasses alone lived an average of 11.5 

 days. 



Without food or water 50 weevils, just developed but not fed, lived 

 an average of 5 days; 15 which were 7 weeks old lived 6 days; and 

 18 which were one month old lived 7.5 days. 



Table XIV. — Duration of life of boll weevils with normal food. 



July-September 



September-November . 



Total for weevils fed on bolls . 



February- July 



October-December . 



Total for weevils fed on foliage. 



April-June 



June-July 



August-September . 

 September-October . 

 October-December . 



Total for weevils fed on squares. 



Sustenance provided. 



Bolls.. 

 ....do. 



Foliage . . 

 ....do... 



Squares. 



do.. 



.....do.. 



do.. 



do.. 



Num- 

 ber of 

 wee- 

 vils. 



82 



4,201 

 92 



4, 353 



170 

 91 

 64 

 18 

 10 



353 



Number 



of weevil 



days. 



684. 5 

 981.0 



1,665.5 



103, 931. 1 

 2.950.9 



106,1 



12, 439. 4 

 3,363.2 

 4, 796. 

 1, 170. 

 359.0 



22, 127. 6 



Avcr- 



lon- 



gevity. 



18.5 

 21.8 



20.3 



24.3 

 32.0 



24.5 



73.1 

 36.9 

 74.9 

 65.0 

 35.9 



62.7 



Maxi- 

 mum 

 lon- 

 gevity. 



+ 20 



69 



130 



130 



105 



58 



135 



+76 



135 



These records show the following longevity for weevils fed on 

 different portions of the cotton plant: On bolls, 20.3 days; on foliage, 

 24.5 days; on squares, 62.7 days. The sustaining power of foliage is 

 therefore about 20 per cent higher than that of bolls, and that of 

 squares 150 per cent higher than that of foliage. This indicates that 

 the squares are by far the most suitable form of food. 



A number of observations were made on the relative longevity of 

 weevils of different generations when fed upon cotton squares. 

 Weevils of the first generation lived 57 days; of the third, 48.5 days, 

 and of the fifth, 65 days. 



Newly reared weevils evidently have not the vitality of weevils 

 emerged from a long hibernation, for they can not live so long on 

 water alone. The boll weevil can find nourishment in several species 

 of malvaceous plants which will sustain life twice as long as water 

 alone, and in certain conditions as long as. cotton foliage. It is inter- 

 esting to note that the sweetened water from sorghum cane had 

 almost three times the sustaining power of pure water. 



In connection with these studies figures were obtained upon the 

 relative food value of the various foods to the two sexes. The data 

 obtained may be tabulated as follows. 



28873°— S. Doc. 305, 62-2 4 



