44 BULLETIN 926, U. S. DEPARTMENT OF AGRICULTURE. 
The average period from oviposition to adult of all weevils bred 
under insectary conditions on upland cotton squares was 14.91 days. 
On sea-island cotton the average period from egg to adult for all 
weevils bred under insectary conditions was 14.94 days. 
The field-bred weevils showed more vitality than weevils bred 
under artificial conditions. 
Under field conditions the average length of time the infested 
squares hung on the upland cotton plants after egg puncture was 11.5 
days. The time required to complete the development of the im- 
mature weevil after the infested square dropped to the ground was 
10.8 days in upland cotton squares. 
There was practically no difference shown in the length of the 
developmental period of the boll weevils bred in short-staple upland. 
long-staple upland, and sea-island cotton squares. 
The developmental period of the boll weevil was approximately 
7.5 days longer under field conditions than under insectary condi- 
tions at Madison, Fla. 
Soil temperatures of 120° F. and higher are usually fatal to the im- 
mature weevils under field conditions. 
The boll weevil at Madison, Fla., shows a decided tendency to 
form a new variety. 
The hibernation of the weevil at Madison, Fla., is incomplete and 
the adults are seldom inactive more than 30 days at a time. 
The emergence from hibernation of the weevil in Florida is very 
gradual, the total daily emergence bearing a direct relation to the 
total daily rainfall. 
Weevils survived the winter in larger numbers in cages set on 
the ground in the woods than in the open field or in cages in trees 
10 feet above ground. Weevils placed in hibernation cages on 
November 15 survived in larger numbers than on any other date 
of installation. 
The percentage of total emergence from hibernation begins with 
more acceleration in Florida than in Texas up to the time that 25 
per cent emerges. After 25 per cent of the weevils have emerged in 
Florida the emergence is less rapid and the Florida emergence curve 
very closely approaches the emergence curve for Louisiana. 
The total percentage of hibernating weevils that survived the 
winter of 1918-19 at Madison, Fla., was 7.54. 
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