LAEGE-CAGE EXPERIMENTS, KEATCHIE, LA., 1905-6. 



47 



At Victoria in the spring of 1904 the period of emergence from 

 iiibernation was determined in the fiekl under exceptionally favor- 

 able conditions. A severe drought, occurring immediately after 

 most of the cotton had been planted, so retarded germination that 

 the sprout cotton developed nearly two months in advance of 

 the planted. Large numbers of weevils emerged before most of the 

 planted cotton was through the ground. Practically the only food 

 supply afforded these weevils was found in the sprout cotton. By 

 reducing the number of sprout plants upon a field of 65 acres it was 

 possible to examine at frequent intervals all of the plants. Since 

 all weevils found at each examination were collected and removed 

 from the field those found at the next subsequent examination may 

 be considered as having emerged in the interval. The development 

 of squares upon the most advanced plants was not sufficient to 

 make it possible for any weevils of the first generation to have become 

 adults before June 1 . The collections from the sprout plants were 

 continued until May 26, and it is probable that some weevils emerged 

 from hibernation after this date. Our knowledge of the weevils at that 

 time was not such as to enable us to distinguish accurately between 

 hibernated and recently emerged adults after that date. For that 

 reason May 26 was considered as representing the conclusion of 

 emergence from hibernation, although it probably continued longer. 



Table XXIV. — Relation of accumulated effective temperature to accumulated emergence 

 in field observations at Victoria, Tex., in 1904- 



Periods. 



Fel). 1-28 



Mar. 1-18 



Mar. 19-25 



Mar. 26-31.... 



Apr. 1-5 



Apr. 6-12 



Apr. 13-16.... 

 Apr. 17-May 1 



May 2-11 



May 12-19 



May 20-26 



Accumu- 

 lated 

 effective 

 tempera- 

 ture. 



F. 



508.0 

 585.5 

 ,117.5 

 ,240.0 

 ,378.5 

 ,537.0 

 ,656.0 

 ,104.0 

 ,374.0 

 ,584.0 

 ,814.5 



Accumu- 

 lated 

 number 

 of plants 

 of cotton 

 sprouts 

 examined. 



None. 

 250 

 650 

 1,190 

 1,720 

 2,120 

 2,320 

 2,570 

 2,990 

 4,163 

 5,900 



Accumu- 

 lated 

 percentage 



of plants 

 examined 



to entire 



nmnber 

 examined. 



None. 

 4.2 

 11.0 

 20.1 

 29.1 

 35.9 

 39.3 

 43.5 

 50.6 

 70.5 

 100.0 



Accumu- 

 lated 



niunl)er of 

 weevils 

 found. 



None. 



19 



39 



65 



100 



160 



200 



224 



376 



521 



648 



Accumu- 

 lated 

 percentage 

 of weevils 

 at each date 

 to entire 

 nimiber 

 found. 



None 

 2.93 

 6.01 

 10. OS 

 15.40 

 24.60 

 30. *C 

 34.50 

 58. OC 

 81. Of 



100. 00 



A comparison of Tables XXIII and XXIV shows that there was a 

 much greater accumulation of temperature at Victoria for the same 

 percentage of emergence than occurred at either Dallas or Keatchie, 

 although the Keatchie record appears to exceed the Victoria record 

 in the amount of accumulated temperature accompanying complete 

 emergence. It seems very probable that in the field records the 

 accumulations are excessive because of two facts; first, at each 



