RECENT STUDIES OF THE MEXICAN COTTON BOLL WEEVIL, 29 



Table XVIII. — Data on the developmental period of the boll weevil — Continued, 

 ARIZONA WEEVILS. 





Larval 

 food. 



Period of 

 oviposition. 



Males. 



Females. 



<B 



u 



3-° 



o 

 Eh 



V 

 8 . 



03 

 03 

 O 



En 



03 



ft 



Nature of 

 weevils. 





[> to 



h 



* "fcj 

 > 3 







go 



o 

 <j 



First generation. . . 

 Do 



Co 1 1 o n 



squares. 



Sept. 2-24 



May 27 



20 



2 

 1 

 3 

 2 



353 



38 

 18 

 55 

 49 



Days. 

 17.6 



19.0 

 18.0 

 18.3 

 24.5 



12 



207 



Days. 

 17.2 



32 



2 

 1 

 5 

 5 



560 



38 



18 



92 



125 



Days. 

 17.5 



19.0 



Do 



. . do 



Sept. 20 









18.0 



Do 



Do 



...do.... 

 Cot ton 

 bolls. 



Cot ton 

 forms. 



Cotton 



squares. 



...do.... 



...do.... 



Sept. 3-10 



Sept. 12-15 



May, Sept.., — 



Sept. 7-Oct. 2... 



June 6- July 3 . . . 

 July 2-15 



2 

 3 



37 

 76 



18.5 

 25.3 



18.4 

 25.0 







True tliurbe- 

 rix. 



28 



513 



18.3 



17 



320 



18.8 



45 



833 



18.5 



Male grandis by fe- 

 male tliurberix: 

 First genera- 

 tion. 



Do 



Second genera- 

 tion. 



11 



20 

 15 



218 



270 

 212 



19.8 



13.5 

 14.1 



13 



19 

 11 



228 



257 

 157 



17.5 



13.5 

 14.2 



24 



39 

 26 



446 



527 

 369 



18.5 



13.5 

 14.1 



Total . 



46 



700 



15.2 



43 



642 



14.9 



89 



1,342 



15.0 





Cot ton 



squares. 



...do 



Sept.5-Oct. 4... 



May 30- June 15. . 



June 16-30 



July 1-7 





Male tliurberix by 

 female grandis: 

 First genera- 

 tion. 



Do 



22 



83 

 35 

 17 

 21 



387 



1,415 

 453 



208 

 293 



17.5 



17.0 

 12.9 

 12.2 

 13.9 



15 



73 

 39 

 18 

 29 



265 



1,049 

 510 

 226 

 389 



17.6 



14.3 

 13.0 

 12.5 

 13.4 



37 



156 



74 

 35 

 50 



652 



2,464 

 936 



434 



682 



17.6 

 15.7 



Do 



Do 



...do.... 

 ...do 



13.0 

 12.4 



Second genera- 

 tion. 



June 24- July 6.. 



13.6 



Total 



178 



2,756 



15.4 



174 



2,439 



14.0 



352 



5,195 



14.7 





1 



1913. 





Total of all 



791 



11,897 



15.0 



722 



10, 487 



14.5 



1,513 



22,384 



14.7 



varieties. 









The total developmental period was also tested in the buds of 

 Hibiscus syriacus during September and October. Three tliurberix 

 varied from 15 to 17 days, with an average of 16 days, and 2 grandis 

 gave a period of 17 and 18 days, or an average of 17.5 days. 



GENERATIONS. 



In order to determine definitely the possible number of genera- 

 tions of weevils in one season two series were carried through the 

 breeding season. These were to determine the maximum and mini- 

 mum number of generations in cotton squares from the first hiber- 

 nated females to emerge in the spring. 



In the maximum series the first eggs from the first hibernated 

 females found were saved for the emergence of the adults. The 

 first of these adults to emerge were mated, their first eggs saved, and 

 so on through each generation. Table XIX shows the results of this 

 series. 



