) 
BIOLOGY OF THE MEXICAN COTTON BOLL WEEVIL. Die 
of the same series required 718 weevil days, or an average develop- 
mental period from egg to adult of 21.8 days. The dévelopmental 
period for both sexes under field conditions averaged 21.1 days from 
egg to adult. 
The total percentage of the infested squares producing adult 
weevils could not be determined, as a considerable number of the 
infested squares under observation were detroyed by ants, Sole- 
nopsis sp. (fig. 10). 
COMPARISON OF THE DEVELOPMENTAL PERIOD OF THE IMMA- 
TURE STAGES OF THE BOLL WEEVIL UNDER FIELD AND IN- 
SECTARY CONDITIONS. 
The results of the breeding experiments under outdoor insectary 
conditions, conducted primarily to check the field breeding records, 
are tabulated and summarized in Table XIII. The average develop- 
mental period under insectary conditions for the hibernated and 
first-generation weevils in upland cotton squares was 14.5 days. 
The developmental period of the progeny produced by first genera- 
tion weevils in long-staple upland and sea-island cottons was 14.2 
and 13.7 days, respectively. There is little if any difference in the 
length of the developmental period of the weevils bred in the 
three types of cotton squares under insectary conditions. A total 
of 1,148 weevils which required 16,568 weevil days or an average 
period of 14.3 days for development under insectary conditions is 
recorded for the three types of cotton. 
The developmental period of the immature stage of the boll weevil 
under normal fieid conditions on short-staple upland, long-staple 
upland, and sea-island cottons is presented in Table XIV. The male 
weevils bred in upland cotton squares required 21.7 days for develop- 
ment from egg to adult and the females of the same series required 
a slightly longer period—22.33 days. A total of 323 weevils bred 
in upland cotton squares under normal field conditions required an 
average period of 21.9 days for development from the time the egg 
was deposited to emergence of the adult weevil. 
In sea-island cotton squares 92 male weevils required 2,006 weevil 
days, or an average period of 21.8 days, for development from egg 
to adult. The 75 female weevils bred from the same source required 
1,651 weevil days or an average period of development of 22 days. 
Both sexes required an average developmental period of 21.9 days 
from egg to adult. 
On long-staple upland cotton 35 male weevils bred in squares 
under field conditions required 726 weevil days or an average period 
of 20.7 days for development of the immature stages. The 26 female 
weevils required 549 weevil days or an average period of 21.8 days 
for development. Both sexes bred in long-staple upland cotton 
squares required an average period of development of 20.9 days from 
egg to adult. 
