RECENT STUDIES OP THE MEXICAN COTTON BOLL WEEVIL. 



23 



The maximum number for females fed only on buds and blooms of 

 Callirrhoe involucrata was 3 eggs. 



The maximum for females fed only on the buds and blooms of 

 Hibiscus syriacus was 8 eggs. 



RATE OF OVIPOSITION. 



The daily rate of oviposition has already been shown in the discus- 

 sion of the general fecundity of the weevils, but the rate by fractions 

 of the oviposition period of the different females is also of interest. 

 In the following studies the oviposition period of each female has 

 been divided into thirds and the results tabulated accordingly. This 

 is shown in Table XIV. 



Table XIV.- — Rate of oviposition of the boll weevil obtained in all experiments. 





Number 



of 

 females. 



Season. 



Kate of oviposition. 



Nature of weevils. 



First third of 

 period. 



Middle third of 

 period. 



Last third of 

 period. 





Total 

 eggs. 



Daily 

 average. 



Total 

 eggs. 



Daily 

 average. 



Total 

 eggs. 



Daily 

 average. 



Hibernated grandis 



2 

 5 

 9 



6 



4 

 3 



2 



3 



2 





136 

 521 

 492 



415 



234 



77 



142 



155 



81 



6.5 

 9.0 

 5.2 



4.7 



5.5 

 2.4 



5.6 



4.0 

 3.9 



161 

 484 

 590 



386 



130 



83 



283 



127 

 101 



7.3 

 8.2 

 6.0 



4.3 



3.1 

 2.5 



9.5 



3.2 



4.4 



105 

 155 

 310 



219 



46 

 67 



189 



61 



63 



4.6 



females. 



Once fertilized 

 grandis females. 



Grandis females 

 with a complete 

 record on copula- 

 tion. 



Various breeding 

 series of grandis. 



Pure thurberix 



June to September 



July to August 



June to September 



September to October. 

 .. do 



2.5 

 3.0 



2.3 



1.0 



2.0 



male thurberix 

 and female gran- 

 dis. 





7.2 



male thurberix 

 and female gran- 

 dis. 

 Positive crosses of 

 male grandis and 

 female thurberix. 



September to October. 



1.5 



2.7 



male grandis and 

 female thurberix. 







Total 





2,253 



5.2 



2,345 



5.4 



1,215 











2.9 

















Here it is seen that the maximum rate of oviposition in the average 

 of all series is reached in the middle period and the minimum is in 

 the last period. However, there are several exceptions to this in the 

 averages of the different types of females. It is interesting to com- 

 pare the results of the spring and fall series. In the former the aver- 

 age of the middle third is much higher than the first and the last is 

 only slightly lower, while in the fall series there is generally a great 

 decrease in the latter part of the period. This difference is of course 

 due to the temperature increasing from spring to summer and 

 decreasing in the fall. 



