THE CONCHUELA. 



31 



Egg-laying capacity. — A summary of the laboratory records 

 regarding egg-laying capacity is presented in the following table : 



Table VI. — Egg-laying capacity of specimens of the conchuela collected in cotton fields . 



Lot. 



When 

 collected. 



Number of 

 females. 



Average 

 number of 

 eggs depos- 

 ited per 

 female. 



Maximum 

 number of 



female. 



A 



1905. 

 July 6 

 Aug. 12 

 Sept. 12 

 Oct. 13 



21 

 8 

 14 

 10 



131 

 74 

 91 

 



321 

 (a) 

 6 122 

 



B 



c 



D 



a No individual records kept for this lot. 



b This record is for the only female specimen isolated from others of same sex. 



The above records are based on females collected in the field, lot 

 A at Tlahualilo, Mexico, and the remaining lots from Barstow, Tex. 

 In all cases it may be presumed that the specimens had deposited 

 eggs before the records began. From the fact that few nymphs 

 were present, while the number of adults was rapidly increasing in 

 the field where lot A was collected, it is probable that the migrating 

 insects consisted of males and females which had recently reached 

 maturity in the surrounding mesquite and arrived at the cotton field 

 as a consequence of their search for a better food supply. The status 

 of these insects in the mesquite as hereafter described adds further 

 evidence to the support of this supposition. If we consider, accord- 

 ingly, that the individuals of lot A had averaged to begin egg-laying 

 one week before the above records begin, the daily rate being the 

 same as for the remainder of the month, the average number of 

 eggs deposited by each female of the lot would be 150 and the maxi- 

 mum number 340. 



Duration of fertility. — Four lots of insects were used in testing the 

 duration of fertility in isolated females. The results are summar- 

 ized as follows: 



Table VII. — Duration of fertility in females of the conchuela isolated from males. 



Lot 

 number. 



Number 



of 

 females. 



When 

 isolated. 



Deposition of first 

 infertile egg. 



Deposition of last 

 fertile egg. 



Date. 



Number 



of days 



after iso- 



tion. 



Date. 



Number 



of days 



after iso- 



tion. 



1 



2 



3 



4 



Average 



5 

 1 



5 

 2 



1905. 

 July 10 

 July 10 

 July 10 

 July 11 



1905. 

 Aug. 11 

 Aug. 7 

 Sept. 10 

 Aug. 16 



32 

 28 

 60 

 36 



1905. 

 Aug. 26 

 Sept. 14 

 Sept. 10 

 Aug. 23 



47 

 66 

 60 

 44 





39 



54 











