BIOLOGY OF THE MEXICAN COTTON BOLL WEEVIL. 33 
hatching out the number that live to enter hibernation is greatly 
decreased. The cessation of squaring naturally forces a considerable 
number of weevils to attack bolls which otherwise might escape. 
Whether the loss resulting from this attack is offset by an advantage 
to the crop of the next season on account of the presence of fewer 
hibernated weevils has not been fully determined. 
THE MAXIMUM NUMBER OF GENERATIONS OF THE BOLL WEEVIL UNDER 
FIELD CONDITIONS. 
The number of generations of the boll weevil under field conditions 
varies with the different seasons and on the different types of soil. 
A very dry and hot season may affect either generation to such an 
extent that the eggs deposited during the first half of the generation 
may not produce weevils at all, and consequently the generation is 
much prolonged. The following table shows the maximum number 
of generations at Madison, Fla., under field conditions: 
TABLE XVI.—MVarimum number of generations of the boll weevil bred in cotton 
squares, Madison, Fla. 
| Period Period 
from from 
Generation. Date. neato Generation. Date. feel 
matur- matur- 
ity. ity 
First generation: Days. Fourth generation: Days. 
Eggs deposited.....-..---.-- June ssle eee Bese pOstLed se see eee ANI SE DARA et 
Generation mature........-. JUIN 22 |\oacssceuc Generation mature.........-- Sept. 16 30 
Second generation: Fifth generation: 
Eggs deposited....-------.- Iiwine SW |icsaccedee Hest 6 pOsitedsasea-=—ee eee SEIN 2S} lenococae 
Generation mature........-.| July 20 29 Generation mature.........-- Oct. 16 32 
Third generation: : Sixth generation: 
Eggs deposited.._.---.------ Jith ya 2Su | eee Hgesidenositeds ss - eee OCS TOA eases 
Generation mature......---. Aug. 17 29 Generation mature.......-..- Noy. 17 33 
The average date of killing frost at Madison, Fla., according to the 10-year average of the United States 
Nicaaher Bureau, is November 29, therefore only six generations of weevils could develop under field con- 
itions. 
HIBERNATION OF THE BOLL WEEVIL IN FLORIDA. 
During the winter of 1918-19 three series of hibernation experi- 
ments were conducted to determine the percentage of weevils sur- 
viving the winter at Madison, Fla. The experiments were arranged 
to secure data on the number of weevils surviving the winter in the 
open fields and along ditch banks, in the woods on the ground among 
the leaves and other rubbish, and in the moss covered trees in the 
woods (figs. 18, 14, 15). 
Large wire screen cages 3 by 3 feet by 4 feet high were used for 
the hibernation experiments. The cages in the fields and on the 
ground in the woods were filled with an equal amount of moss, leaves, 
and cornstalks to represent approximately the material the weevils 
would hibernate in under normal conditions. The cages installed 
