BIOLOGY OF ARIZONA WILD COTTON WEEVIL. 



13 



several Thurberia plants growing so close that some branches over- 

 lapped the cotton. 



LIFE-HISTORY STUDIES. 



FECUNDITY. 



A number of series of Thurberia weevils were tested to determine 

 the fecundity of the females on the different foods. 



WEEVILS FED ON COTTON SQUARES. 



During the season 14 pairs of weevils were mated on cotton squares 

 in glass tumblers and the fecundity determined. These weevils 

 either emerged from or were removed from their hibernation cells 

 in Thurberia bolls collected at different points in the Santa Catalina 

 and Santa Bita Mountains. They were all hibernated individuals. 

 Nearly all were left on cotton squares until the close of the experiment, 

 but two were removed from this food after 17 days and fed on cotton 

 bolls for the remainder of the period. 



Of the 14 females thus mated, 13 oviposited more or less normally. 

 The other one, placed with cotton squares August 31, deposited one 

 egg October 5 and another one October 7 and then stopped. This 

 female was still alive and feeding at the close of the experiment on 

 November 8. The data showing the activities of the 13 normal 

 females are given in Table II. 



Owing to the shorter active season to which the Arizona weevils 

 are accustomed, it seemed quite probable that the average fecundity 

 of the females would not equal that of the Texas weevils, but this is 

 seen not to be the case. These averages secured with thurberiae on 

 cotton squares in 1914 are very nearly as high as those from the 

 best series of grandis reared in Texas on the same food in 1913, and 

 they are higher than the general average of all series of grandis. 



Table II. — Fecundity of Anthonomus grandis thurberiae mated on cotton squares, 

 Agua Caliente ranch, Arizona, 1914. 



Source of weevils. 



Date 

 first fed 

 squares. 



Date 

 first egg. 



Period 



fed 

 squares 

 to dep- 

 osition. 



Date 



last eggs. 



Ovi- 



posi- 



tion 



period. 



Total 

 eggs. 



Aver- 

 age 

 eggs 

 per 

 day. 



Date 



female 

 dead. 



Date 

 male 

 dead. 



Emerged from cells in 

 Thurberia bolls 



Removed from cells 



in Thurberia bolls. . 



Do 



June 23 



June 25 



July 8 



...do 



...do 



July 11 

 ...do 



Aug. 11 



...do 



...do 



Aug. 31 

 ...do 



July 5 



July 15 

 July 12 

 July 13 

 July 15 



...do 



...do 



Aug. 21 

 Aug. 20 

 Sept. 1 

 Sept. 12 

 Sept. 7 

 Sept. 12 



Days. 

 13 



20 

 4 

 5 

 7 

 4 

 4 



10 

 9 



20 



12 

 7 



12 



Aug. 10 



Aug. 7 

 Aug. 31 

 Aug. 14 

 Aug. 19 

 Aug. 28 

 Aug. 13 

 Sept. 16 

 Oct. 31 

 Nov. 2 

 Nov. 4 



...do 



Oct. 19 



36 



24 

 51 

 33 

 36 

 45 

 30 

 27 

 72 

 62 

 54 

 59 

 38 



176 



116 



82 



150 



126 



217 



144 



92 



309 



299 



156 



39 



141 



4.9 



4.8 

 1.6 

 4.5 

 3.5 



4.8 

 4.8 

 3.4 

 4.3 

 4.8 

 2.9 

 .7 

 3.7 



Aug. 10 



Aug. 7 

 Sept. 14 

 Aug. 11 

 Aug. 24 

 Aug. 30 

 Aug. 14 

 Sept. 19 



July 12 

 Sept. 11 

 Aug. 14 

 Sept. 4 

 Sept. 11 



Do 



Do 



Do 



Do 



Do 



Do.. .. 





Do 







Do 





Oct. 31 



Do. 1 





Sept. 12 



Do.i L..do 



| 



Oct, 19 



Total ' 



' 127 

 9.7 



567 2,047 

 43.6 157.4 













3.4 

 4.9 



.7 







Maximum < ! 



20 



4 



72 

 24 



309 

 39 























These weevils were fed on squares until Sept. 17, and then on bolls. 



