20 



PAPERS ON THE COTTON BOLL WEEVIL, ETC. 



passes 68 : F. the first weevils commence to emerge from hibernation, 

 and this conclusion is confirmed by all of our observations. 



It will be seen from the temperature curves in figure 2 that at 

 Victoria the normal mean temperature usually reaches 68° about April 

 1 and at College about April 15. Figure 2 shows that in 1903 the mean 

 average temperature r<acbei 68 about one week later at Victoria. 

 In 1904 (fig. 2) the mean temperature reached 68° about March 10 at 

 Victoria and the first weevils were found about the middle of March, 

 which is also true of Lavaca County, while at College Station 68° was 

 reached a week later than usual, but the t°mperature was above 66° 

 for the month preceding April 15. If the mean rise in temperature 

 from February 15 to May 15 be plotted, the line would reach 68° 

 about April 5, which very closely approximates the date of the first 



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Fig. G. — Comparison of normal temperatures, October 15 to June 15, tor various districts in Texas. 



appearance of the weevils at College Station for that year. From all 

 the data available, therefore, it seems very safe to assert that when 

 the temperature reaches 68° or has been above 65 c for several weeks 

 the first weevils will emerge. By consulting figure 6 this time may 

 be seen for any section of the State. The curve shows that weevils 

 would normally emerge from hibernation about 10 days earlier in the 

 southwestern and coast countries than in central and northeastern Texas, 

 and about 20 days earlier than in northwestern or western Texas. 



The greatest number of weevils emerge considerably later and usu- 

 ally about the time cotton commences to Square. The time of the 

 principal emergence and the beginning of general oviposition by the 

 hibernating brood is practically the same. A few belated weevils 

 appear after this time, as is shown by the field records of Mr. Telt- 

 schick for 1903 and 1901. For if the bulk of the weevils emerges at the 



