26 



BULLETIN 358^ U. S. DEPARTMENT OP AGRICULTURE. 



CESSATION OF OVIPOSITION BY HIBERNATED WEEVILS. 



Observations on the date of cessation of oviposition were made with 

 45 hibernated females collected in the field early in the season and fed 

 on cotton squares. As shown in Table XXI the dates ranged from 

 June 9 to August 23 and the average date of cessation in both series 

 was July 17. All the females excepting two laid eggs on June 20 or 

 later and a majority laid eggs well along in July. Since these females 

 were nearly all selected from the first to appear in the spring it is 

 certain that the later emerged adults would continue to oviposit con- 

 siderably longer in the fall. Thus the futility of late planting of 

 cotton to escape boll weevil attack is seen. 



Table XXI. — Dates of cessation of ovijwsition of first hibernated females of the boll 



weevil. 



With males throughout life. 



Females isolated 



from males in 



spring. 



With males throughout life. 



Females isolated 



from males in 



spring. 



Date collected. 



Date 

 stopped 

 ovipos- 

 iting. 



Date 

 col- 

 lected. 



Date 

 stopped 

 ovipos- 

 iting. 



Date collected. 



Date 

 stopped 

 ovipos- 

 iting. 



Date 

 col- 

 lected. 



Date 

 stopped 

 ovipos- 

 iting. 



May 26 



Aug. 3 

 June 9 

 June 26 

 June 29 

 July 5 

 June 28 

 June 18 

 July 19 

 July 10 

 July 12 

 July 8 

 July 31 

 June 23 

 July 31 



Junel 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.:.. 



June 29 

 July 10 

 Aug. 22 

 July 19 

 July 21 

 June 28 

 July 8 

 July 19 

 June 30 

 Aug. 4 

 July 4 

 July 30 

 Aug. 17 

 July 17 



June 17 



Aug. 23 

 July 18 

 July 14 

 June 20 

 Aug. 4 

 Aug. S 



..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 ..do.... 

 do 



July 15 

 Aug. 13 

 July 3 

 Aug. 23 

 July 17 



Do 



Do 



Do 



Do 



Do 



Do 



Do 



Do 



Do 



Do 



Do 



Earliest date stopped. . 

 Latest date stopped . . . 

 Average date stopped . 



Aug. 20 

 July 22 

 July 24 

 July 3 

 July 7 

 June 26 



Do 





do 



Do 





do 



Do.. 





do 



Do 





do 



Do . . 



June 9 

 Aug. 23 

 July 13 





Do 



Aug. 23 





July 20 





TOTAL DEVELOPMENTAL PERIOD. 



Olservations of 191 4-. — The time required from egg deposition to 

 adult emergence was observed with all weevils bred in the various 

 series until September 5. The maximum developmental period of 

 any weevil was 20 days a.nd the minimum period was 11 days. The 

 results are tabulated according to season and generation in Table 

 XXII. 



