14 PAPERS ON THE COTTON BOLL WEEVIL, ETC. 



hibernation in southern Texas, normally onty about 2 per cent, and 

 never over 5 per cent, survive under field conditions at College Station, 

 and about 2£ per cent in the Brazos bottom at Wellborn. In other 

 words, only about one-fifth as many weevils survive the winter here as 

 do in southern Texas. Whether a corresponding difference will be 

 found in the mortality between central Texas and northern Texas 

 remains to be determined. This will depend on the weather condi- 

 tions discust below, but it seems doubtful that there will be so great 

 a difference. 



TIME OF GREATEST MORTALITY DURING HIBERNATION. 



In Table I it may be seen that in lots 1, 5, and 6, including 600 

 weevils, there was a mortality of at least 51 per cent during the month 

 of December, and that in lot 5 there was a mortality of 9.6 per cent 

 during January and but 2.8 per cent during the remainder of the 

 year. Referring to figure 2 it may be seen that at College Station in 

 the winter of 1903-1 the rainfall was greatest in December, while 

 during the balance of the winter it was below normal. The maximum 

 in December approached the normal, whereas usually the maximum N 

 for winter occurs in January. The temperature was very close to 

 normal thru January, but considerably above normal daring* the 

 remainder of the winter. 



In general, an excessive rainfall seems to be a most important factor 

 in increasing the mortality of the weevil. The temperature does not 

 usually depart sufficiently from the normal to be an important factor, 

 except that when occurring with a deficient rainfall an excess of tem- 

 perature appears to be decidedly beneficial to hibernation. By refer- 

 ring to figures land 5, showing the normal rainfall and temperature for 

 Hallettsville, Tex. , and the monthly mean temperature and rainfall dur- 

 ing the winters of 1899-1900, 1900-1901, 1902-3, and 1903-1, it may be 

 seen that in 190C-1901 there was a decided deficiency in rainfall and a 

 slight excess in temperature, whereas in 1902-3 there was an abnor- 

 mally large rainfall and a nearly normal temperature. In 1901 and 

 1901 the weevils survived in unusally large numbers, while in 1903 

 the number hibernating successfully was considerably less than nor- 

 mal. The same general conclusions are shown when the rainfall and 

 temperature records as given for College and Brenham in Table III 

 are compared with the percentage of weevils surviving at College and 

 in the Brazos bottom below Wellborn. The rainfall and temperature 

 records are shown diagrammatically in figures 2 and 3, giving also 

 the normal rainfall and departure from normal for College Station 

 and Victoria in 1902-3 and 1903-4. 



If it be true that the rainfall is the most important climatic factor 

 in the mortality of the hibernating weevils, it is interesting to com- 

 pare the rainfall of different sections of the State as given by the 



