44 



EIBEBNATION OF THE COTTON BOLL WEEVIL. 



Table XX. — Relation of effectivi temperatures to emergena at Keatchie, La., mid 



Dallas, Tex., 1906. 



Periods of emergence. 



Mar. 15-21 



Mar. 22 27 



Mar. 28 \|>r. 2. 



Apr. 3 L3 



Apr. 11 20 



Apr. 21-May 5. 

 May 6-13..'.... 



May 14-23 



May 24-29 



May 30-June 11 

 June 12-30 



Total effective Average effective 

 temperature. temperature. 



Keatchie. Dallas. Keatchie. Dallas 



°F. 



12.0 

 1 ll.d 



37.0 

 275.5 

 L18.S 

 484.7 

 176.0 

 339.0 

 201.0 

 413.0 

 667.0 



°F. 



5.5 

 L51.8 

 66.6 

 243.6 

 124.1 

 435. 8 

 159.8 

 300.2 

 L96.8 

 47s. 

 700.0 



'F. 



1.7 

 23.5 



7.4 

 25.0 

 16.9 

 32.3 

 22.0 

 33.9 

 33.5 

 37.5 

 39.2 



°F. 



0.7s 



25.3 



ll.l 



22.14 



17.7 



29.0 



19.9 



30.0 



32.8 



Number of weevils 

 emerging. 



Keatchie. Dallas 





 25 

 12 



165 

 28 



L87 

 49 



173 

 23 

 65 



Ail 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 emergence to increase in effective temperature at Keatchie, 

 La., and Dallas, Tex., 1906. 





Keatchie, La. 



Dallas, Tex. 







Range of 

 effective 







Total num- 

 ber of 



Per cent. 

 based on 









tempera- 



Number of 



Per cent of 



Numl er of 



Per cent of 



weevils 



grand total 



tures. 



weevils 



total 



weevils 



total 



emerged. 



emerged. 





emerging. 



emergence. 



emerging. 



emergence. 







1-14°.... 



20 



2.7 











20 



2.5 



15-20°.... 



52 



7.1 



2 



3.6 



54 



6.8 



21-25°.... 



116 



16.0 



25 



45.5 



141 



17.8 



26-30°.... 



127 



17.5 



is 



32. 7 



145 



is..", 



31-35°.... 



309 



42.4 



10 



L8.2 



319 



40.7 



36-40°.... 



84 



11.5 











84 



10.7 



41-50°.... 

 Total. 



20 



2.7 











20 





728 100.0 



55 



100.0 



7S3 



100.0 



The number of weevils emerging under 1 1 degrees of effective 

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

 emergence increases with the increase in temperature until after a 

 majority of the weevils have emerged. ^Iost weevils left their 

 winter quarters during an effective temperature averaging between 



