42 



BULLETIN 926, IT. S. DEPARTMENT OF AGRICULTURE. 



NUMBER OF BOLL WEEVILS SURVIVING THE WINTER WHEN HIBERNATING IN 

 SPANISH MOSS 10 FEET ABOVE GROUND. 



The data on the survival of the weevils in cages installed 10 feet 

 above ground in trees are presented in Table XX. Only 4.54 per 

 cent of the 4,400 weevils installed in the cages in the trees survived 

 the winter. The cage installed on November 15, however, gave a 

 total emergence of 10.2 per cent. In connection with the dates of the 

 beginning of emergence of the hibernated weevils it is interesting to 

 note the manner in which the moss held back the weevils, the first 

 emergence not occurring before February 26, and the last emergence 

 taking place on July 7. 



Table XX. — Hibernation record of boll weevils in cages installed in the trees. 





Date 

 installed. 



o a 



Date of 

 first 

 emer- 

 gence. 



Date of 

 last 

 emer- 

 gence. 



Date on 

 which 



25 

 per cent 



had 

 emerged. 



Date on 



which 



50 



per cent 



had 

 emerged. 



Date on 

 which 



75 

 per cent 



had 

 emerged. 



a 



11 

 o§ 



_. G> 



_o 



<D 



Number 

 emerged. 



> 



o 



03 fl 



p 



0) 



w 



EH 

 B 

 CO 



©—: 



Cage 

 No. 



J. 



03 



"oS 



a 



O 

 Eh 



s> 



3 



1918. 

 Oct. 1 

 Oct. 15 

 Nov. 1 

 Nov. 15 

 Dec. 1 



1,000 

 1,000 

 1,000 

 1,000 

 400 



1919. 



1919. 



1919. 



1919. 



1919. 



Days 





 106 

 113 

 112 

 83 





 33 

 20 

 60 



6 





 27 

 18 

 42 



5 





 60 

 38 

 102 

 11 



10 

 10 

 10 

 10 

 10 







6 



9 



12 



15 



Mar. 3 

 Mar. 6 

 Mar. 4 

 Feb. 26 



July 1 

 July 7 

 July 5 

 May 20 



Apr. 2 

 May 10 

 Apr. 7 

 Feb. 26 



Apr. 9 

 June 2 

 May 5 

 Mar. 8 



Apr. 14 

 June 4 

 June 2 

 May 4 



6.0 

 3.8 

 10.2 

 2.7 



Total 



4,400 

 880 



1,000 

 400 



414 



82.8 

 113 



83 



119 

 23.8 

 60 

 



92 

 18.4 

 42 

 



211 

 42.2 

 102 

 



50 

 10 

 10 

 10 





Av .. 















4.54 

















10.2 





































SUMMARY OF THE HIBERNATION OF THE BOLL WEEVIL UNDER ALL CONDITIONS, 



WINTER 1918-19. 



Table XXI gives a summary of the hibernation records secured 

 at Madison, Fla., during the winter 1918-19. The records show that 

 of 13,100 weevils installed in the three sets of hibernation cages at 

 different dates during the fall of 1918, only an average of 7.54 per 

 cent survived the winter. The highest percentage of survival is 

 shown in the cages installed in the woods on the ground. The second 

 highest percentage of survival was in cages installed in the open field 

 and the lowest percentage of survival in the cages installed 10 feet 

 above the ground. It is also noticeable that in every case weevils 

 placed in the hibernation cages on November 15 survived in greater 

 numbers than those placed in the cages at an earlier or later date. 

 It is evident that weevils that become adult right at the time of 

 entrance into hibernation are not in as good physical condition to 

 go through the winter as weevils that have had time to feed longer 

 and thus get their stomach contents in proper condition for entering 

 hibernation. The maximum survival by the weevils that were placed 



