SEASONAL HISTORY. 



59 



by independent laws of effective temperature. It appears also that 

 the activity is much less on cloudy days than on clear days. At 

 Tallulah, La., in 1910, observations were made on the periodic 

 division of daily oviposition. The results are shown in Table XXI. 



FAHREN 

 HEIT 



TiME 



2p Um 2 3 4 5 6 7 8 9 10 II 12m Ipm 2 3 4 5 6 7 8 9 10 II I2p 



100°- 



95°- 

 90°- 

 85°- 

 80°- 

 75°- 

 70°- 

 65°' 

 60°- 













































































-fe 



pti 



m. 











































>^ 







■^&i 







































,4 





• 









\ 



tf 

































u 

















K ^ 



7^ 

























A 



^ 



'/ 





















^5: — 

















Tn, 





A 



k- 





\ 



Qu 



>ra 



73 ( 



Xct 



'ait 



H 



f^ 



(~err 



a/t' w.evils 





























O 



n Se/olember-3. 



t*J,/.?03 









































































































Fig. 5. — Diagram showing average activity of five female boll weevils. (After Hunter and Hinds.) 



Table XXI. — Summary of periodic division of oviposition, based upon nine boll weevils, 



Tallulah, La., July, 1910. l 



Period. 



Total eggs 

 laid. 



Average 



number of 



eggs per 



hour. 



Per cent 

 of total 

 oviposition 

 iri each 

 period. 



Average 



eggs per 



weevil 



per hour. 



5 p. m.-7.30 p. m 

 7.30 p. m.-4 a. m 

 4a. m.-9a. m... 

 9 a. m.-l p. m... 

 1 p. m.-5 p. m... 



5.00 

 .59 

 2.10 

 2.13 

 4.38 



23.15 

 9.26 

 19.44 

 15.74 

 32.41 



0.63 

 .07 

 .26 

 .27 

 .55 



From these records it may be seen that the warmest part of the 

 day is the most active period for the weevils. 



SEASONAL RATE OF OVIPOSITION. 



Since the period of reproductive activity of the boll weevil is so 

 long, the rate at winch eggs are deposited is a question requiring 

 much time for its determination. The rate of oviposition is at least 

 as strongly influenced by variations in temperature as is the rate of 

 development, and it is very probable that some of the previously 

 unaccountable and abrupt variations in the rate upon succeeding 

 days may be explained by the relative humidity or by the amount of 

 sunshine. The rate is influenced also by the abundance of clean 

 squares which the weevil can find, so that it is greater in the early 

 part of the season as the degree of infestation is approaching its 

 limit than after infestation has reached its maximum. Several 

 series of observations have been made upon the rate of egg deposi- 

 tion. These have been tabulated below in Table XXII. 



i From Cushman, Journ. Econ. Ent., vol. 4, p. 436. 



