BIOLOGY OF THE MEXICAN COTTON BOLL WEEVIL. 37 



ACTIVITY DURING THE HIBERNATION PERIOD. 



In northern Florida the boll weevil, during the period of hiberna- 

 tion, is seldom inactive for a period of time longer than a month. As 

 was pointed out, the only months in which the average mean tem- 

 perature is below 56° F. are December and January, and even then 

 it not infrequently happens that warm days occur such as would 

 force the weevil to activity. Thus it might be said that the hiberna- 

 tion of the boll weevil in northern Florida is incomplete. 



TIME OF EMERGENCE FROM HIBERNATION. 



Owing to the incomplete hibernation of the boll weevil in northern 

 Florida the time of emergence must necessarily be a variable date. 

 February 20 has been selected as the date emergence started in the 

 experimental work at Madison. However, six weevils emerged on 

 the 10th of February and four on the 16th. After February 20 little 

 cold weather is experienced at Madison, and this date may be safely 

 assumed to represent approximately the date when emergence begins 

 for weevils sheltered in places exposed to the direct rays of sunlight. 



RATE OF EMERGENCE OF HIBERNATED WEEVILS IN FLORIDA. 



The emergence period in Florida extended over the period from 

 February 20 to July 7. The rate of emergence was decidedly more 

 gradual than might be expected when the relatively high tempera- 

 tures prevailing during March, April, and May are considered. 

 The accompanying diagram (fig. 16) shows the daily rate of emer- 

 gence of the weevil when hibernating in the open fields, on the 

 ground in the woods, and in the moss on the trees 10 feet above 

 ground. The diagram also shows three prominent periods of emer- 

 gence, or rather accelerations in the rate of emergence — viz, March 

 ■ 3, April 4, and May 5, 6, and 7. On these dates the rainfall varied 

 from 0.1 of an inch on March 3 to 1.75 inches on May 7. The extreme 

 emergence recorded for May 6, 7, and 8 was also probably influenced 

 by excessive temperatures. In the accompanying chart (fig. 17) the 

 total percentage of rainfall compared to the total percentage of 

 weevils emerged at different dates also indicates that excessive tem- 

 perature was operating along with the rainfall after the 6th of May. 



One of the interesting facts concerning the daily emergence of the 

 weevil when hibernating under the three different conditions is that 

 the emergence from the cages containing moss as hibernation quar- 

 ters was much later than the emergence from the other two sets of 

 cages. Spanish moss has been proven to be difficult to warm up 

 sufficiently to force the weevils out of winter quarters before late in 

 the season and the results at Madison, Fla., corroborate this fact in 

 every way. 



