32 



PLANT-BUGS INJURIOUS TO COTTON BOLLS. 



Two points of importance are brought out by the data given in 

 Table VII. First, it is evident that the duration of fertihty after 

 isolation does not cover the normal egg-laying period of the female. 

 Second, the end of the period of fertility in the female is not well 

 marked and a considerable period ma}^ elapse between the deposition 

 of the first infertile egg and of the last fertile egg. 



PROPORTION OF SEXES. 



While observations on a small scale indicated a preponderance of 

 the number of females over the number of males, the final and most 

 conclusive observation as well as the totals show that the two sexes 

 occur in about equal abundance. The difference in favor of the 

 female sex shown in the totals is less than 2 per cent over an equal 

 division, a difference which might occur in any arbitrarily chosen 

 series from a large number of specimens including exactly one-half 

 of each sex. 



Table VIII. — Proportion of sexes of the conchuela. 



When collected. 



Where collected. 



Number of 

 males. 



Number of 

 females. 



Total. 



September, 1904. . . 

 July 11, 1905 



TlahualilOjDurango, Mexico. 

 do 



7 



17 



247 



12 

 25 



253 

 zoo 



19 



42 



July 12, 1905 



.. .do 



Total 







271 



290 5fi1 











LONGEVITY. 



Adults collected in the field. — Provided that an abundance of food 

 is available, the length of life of the adults when protected from 

 their natural enemies is dependent upon the season of the year in 

 which the insects reach maturity. The following tabulations 

 summarize the data concerning this point in the life history of the 

 conchuela derived from the laboratory records. 



Table IX. — Summary of records of longevity of adults of the conchuela collected in cotton 



fields. 



Number of 

 specimens. 



Where collected. 



When col- 

 lected. 



Maximum 



longevity. 



(Days.) 



Average 



longevity. 



(Days.) 



«21 



8 



14 



5 



9 



2 





 11 



Tlahualilo, Durango, Mexico.... 



1905. 

 July 6-10 

 Aug. 12 

 Sept. 12 

 Sept. 19 

 Oct. 13 



U2' 



83 



29 

 &91-1- 

 bQ7+ 



79 

 ■■'og'" 

 "V67+' 



9 



71 

 29 

 17 

 53 

 6 67+ 



37 



"9" 

 "53+ 



do 





Barstow, Tex 





o Apparently parasitized by Tachinid fly but no parasite emerged from body of supposed host. 

 b In hibernation test December 1; all alive December 19; all dead March 8, 1906. 



c Alive January 17, 1906, in hibernation cage; dead March 8, making 98+, but to keep on same basis as 

 Other specimens the record was included only up to December 19, 1905. 



