44 



HIBERNATION OF THE COTTON BOLL WEEVIL. 



Tahle XX. — Relation of rffcrtive temperatures to ewrrgrnee at Keatchie, La..<nid 



Dallas, Tex., 1906. 



Periods of emergence. 



Mar. 15-21 



Mar. 22-27 



Mar. 2S-Apr. 2. 



Apr. 3-13 



Apr. 14-20 



Apr. 21-May 5. 



May 6-13 



May 14-23 



May 24-29 



May 30- June 11 

 June 12-30 



Total effective 

 temperature. 



Keatchie. Dallas 



°F. 



12.0 

 141.0 



37.0 

 275.5 

 118.5 

 484.7 

 176.0 

 339.0 

 201.0 

 413.0 

 667.0 



°F. 



6.5 

 151.8 

 66.6 

 243.6 

 124. 1 

 435.8 

 159.8 

 300.2 

 196.8 

 478.0 

 700.0 



Average effective 

 temperature. 



Keatchie. Dallas 



°F. 



1.7 

 23.5 



7.4 

 25.0 

 16.9 

 32.3 

 22.0 

 33.9 

 33.5 

 37.5 

 39.2 



°F. 



0.78 

 25.3 

 11.1 

 22.14 

 17.7 

 29.0 

 19.9 

 30.0 

 32.8 



Number of weevils 

 emerging. 



Keatchie. Dallas 







25 



12 



165 



28 

 187 



49 

 173 



23 



65 

 7 



An examination of this table shows three very distinct periods of 

 emergence, the first being from April 3 to 13, inclusive; the second 

 from April 21 to May 5, inclusive; and the third from May 14 to 23. 

 No weevils emerged from the Dallas cages after May 23. At Keatchie 

 a fourth period may be considered as occurring between May 30 and 

 June 11. In this place the emergence ceased on June 28. It is 

 noticeable that between June 20 and 27 no weevils had emerged. 

 It will be noticed in the table that the periods of largest emergence 

 are separated by periods having decidedly lower temperatures, 

 during which emergence was decreased, although it did not cease 

 entirely. 



The relation of emergence to 5-degree increments in effective tem- 

 perature is shown in Table XXI. 



Table XXI. 



The relation of en} erg e nee to increase in effective temperature at Keatchie, 

 La., and Dallas, Tex., 1906. 



The number of weevils emerging under 14 degrees of effective 

 temperature, or 57° F., is very small indeed. From that point the 

 emergence increases with the increase in temperature until after a 

 majority of the weevils have emerged. Most weevils left their 

 winter quarters during an effective temperature averaging between 



