LABGE-CAGE EXPERIMENTS. KEATCHIE. LA.. L905 6 



45 



21 and 35 degrees. At Keatchie 75 per cent and at Dallas 96 per cent 

 of the total emergence took place between these limits. Ai Dallas 

 the Largest emergence occurred between 2] and 25 degrees of effective 

 temperature, while at Keatchie the largest emergence occurred 

 between 3 1 and 35 degrees. 



In considering the effect of temperature upon emergence it must be 

 remembered that tin* nature <>!' the shelter within which the weevil 

 hibernates must inevitably have an important bearing on the time at 

 which the weevil becomes active. 



RELATION OF TIME OF ENTRANCE INTO HIBERNATION TO SURVIVAL 



AM) EMERGENCE. 



It has previously been stated that none of these experiments was 

 instituted more than about a week before it became cold enough for 

 practically all weevils to hibernate. For this comparison it is pos- 

 sible to use only the data for t hose sect ions having similar conditions 

 as to (1) the source from which weevils were obtained, (2) the time 

 when they were placed in the cage, and (3) the general nature of the 

 shelter afforded. 



Table XXII. — Relation of time of emergena in 1906 to time of starting hibernation 



in 1905. 



Seel ion 



W lion wee- 

 vils were 

 put in. 



Percentage of total emergence, 1906, occurring in— 



Percenl 



of sur- 

 vival. 





number in 

 cage. 



March. 



April. 



May 1-14. 



May 15- 

 June 1. 



June 2-30. 



Remarks. 



7 and 8 



14, 15, and 

 L6. 



17 



Is 



Nov. 25 



and 29. 



Dec. 3 and 



8. 

 Nov. 28... 



Nov. is... 



3.7 



4.8 



0.7 

 



46.3 



47.4 



41.4 

 28.3 



28.7 



17.1 



24.4 

 15. 



15.7 



24.7 



22.0 

 32.0 



5.5 



5.5 



2.4 

 24.5 



3.0 



3.23 



4.1 

 5.3 



vTexas weevils. 

 Louisiana weevils. 







In the first section of the table, among weevils collected in Texas, 

 it is apparent that there was practically no difference in the time of 

 emergence between those placed in hibernation from November 25 

 to 29 and those started December 3 to 8. In the second part of the 

 table, among the Louisiana weevils, those entering hibernation 

 November 18 emerged more slowly than did those placed in the cage 

 November 28. The explanation of this may probably be found in 

 the fact that the lir>t date was not sufficiently early to insure the 

 death of many weevils by starvation before 1 they could hibernate. 

 It did, however, allow a Larger proportion of them to penel rate deeply 

 into the shelter than in the case of weevils placed in the cage ten days 

 later, which was only one day before a marked decrease in tempera- 

 ture. The weevils placed in the cage on December 3 and 8 experi- 

 enced wanner temperatures than those placed in on the 28th of 

 November, and, therefore, found conditions more favorable for their 



