114 



THE MEXICAN COTTON-BOLL WEEVIL. 



Certain climatic phenomena are likely to occur which will empha- 

 size still more the effects produced by extreme cold and great precipi- 

 tation. At Tallulah, La., in 1910-11, the early freeze on October 29 

 cut off the food supply and was followed by warm temperatures in 

 November which required feeding. The minimum experienced in 

 January completed the control and was low enough to counteract the 

 small precipitation. 



LONGEVITY OF HIBERNATED WEEVILS. 



From the beginning of the hibernation experiments in 1905 it has 

 been the custom to place the emerging weevils in rearing jars or cages 

 to determine the average and maximum longevity with and without 

 food. The data obtained have a bearing upon the proper time for 

 planting and upon other practical points. In these experiments 

 9,295 weevils have been used, as shown in Table L. The fed weevils 

 were furnished cotton squares as soon as they became available. 

 Before that time they were given fresh cotton leaves daily. The 

 unfed series was supplied with water only. Both series were placed 

 in small cages where general conditions closely approaching those in 

 nature were maintained. It should be especially noted that fed 

 weevils show over double the longevity of unfed weevils throughout 

 the season. 



Table L. — Longevity of hibernated boll weevils after emergence. 



It will be noted that the records of longevity of weevils after 

 emergence from hibernation referred to above are based upon speci- 

 mens that had passed the winter in artificial hibernation cages. 

 However, a number of observations have been made upon the lon- 

 gevity of weevils which pass the winter under natural conditions in the 

 field. For instance, March 1, 1906, a number of weevils were collected 

 from cotton bolls at Brenham, Tex. These were placed in small 

 cages and observed daily. The last one died on May 31. Naturally 

 the time tliis weevil was deprived of food the preceding fall is not 

 known, but it must have been prior to December 1, as the frosts had 



