HIBERNATION AND DEVELOPMENT OF BOLL WEEVIL. 17 



Texas section of the U. S. Weather Bureau. The normal total rain- 

 fall during the winter months of December to March for southwestern 

 Texas is 6.4:6 inches, for the coast country 8.26 inches, and for central 

 Texas 9.83 inches, while the total normal effective winter tempera- 

 ture^' during December to March, inclusive, is, for southwestern Texas 

 1,631.4° F., for the coast country 1,190.6° F., for eastern Texas 

 1,483.1° F., for northeastern Texas 934.9° F., and for central Texas 

 1,294.3° F. The average effective temperature for the eastern and 

 southwestern countries is therefore from 200° to 300° higher than that 

 of central Texas for this period and from 450° to 700° F. higher than 

 that of the coast and northeastern Texas. If we consider the more crit- 

 ical period of December to February, inclusive, the southwestern and 

 eastern countries have 300° to 200° F. more effective temperature 

 than central Texas and from 600° to 500° F. more than northeastern 

 Texas. It would therefore seem that both the temperature and rain- ^ 

 fall are far more favorable to the successful hibernation of the weevil 

 in southwestern Texas than in central, coast, or northeastern Texas, and 

 that the conditions as to temperature and rainfall in the coast country 

 during the critical period are very similar. In northeastern Texas, 

 however, as the weevils do not emerge from hibernation until con- 

 siderably later in the spring, the larger rainfall occurring during April 

 may have some effect on them. 



As before mentioned, floods during the period of hibernation seem 

 to have a marked effect upon the mortality of the weevil, as there 

 were notabl}^ fewer weevils thruout the Brazos bottom in this section 

 in the spring following the flood of February, 1903. 



PLACES OF HIBERNATION. 



Considerable time has been spent in attempting to find the places in 

 which the weevils spend the winter, but the results have been rather 

 unsatisfactory. This has also been the experience of many observing 

 practical farmers. Numerous cotton fields were examined in the 

 neighborhood of the college during January and February, 1903, and 

 tho Mr. Newell and the writer made diligent search in all conceivable 

 places over a considerable acreage, embracing an area of 2 miles, ex- 

 amining cornstalks, grass, bark, fence posts, gins, etc., we found but 

 1 live boll weevil during the winter and this one was under a small 

 pile of dried manure. On November 29, 1903, Mr. A. F. Conradi 

 found 2 weevils in a pile of old cotton brush in our experimental field, 

 3 under the bark of a log near the field, and 2 in the cotton field under 

 a bunch of dead cotton leaves. On December 15 a thoro examination 



« Total normal effective temperature is reckoned for each month by subtracting 43° 

 F. (the point at which animal activity is supposed to begin) from the normal mean 

 temperature for that month, multiplying the difference by the number of days in 

 that month, and adding together the four products thus obtained. 



