28 BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



Time of oviposit ion. — One of the most important problems in con- 

 nection with the control of the codling moth in the Grand Valley 

 was to determine when the earliest eggs of the second brood were 

 deposited and when oviposition was at its height. It is believed 

 that these data could best be secured by using moths that emerged 

 from larvae collected regularly from banded orchard trees, since 

 the subsequent emergence of the moths would correspond to that 

 which would naturally have occurred in the field. TTith this in 

 view, the moths from the Hamilton orchard material were kept for 

 oviposition studies, beginning with those that emerged July 12 and 

 ending with those that issued August 19. 



As is given in Table XVI, 69 cages containing a total of 1.711 

 moths were employed and, as will be noted therein, the average 

 number of days before oviposition was 2.07. maximum 5, and mini- 

 mum 1 ; the average number of days from the first to the last ovi- 

 position was 16.78, maximum 25, and minimum 7 ; the average num- 

 ber of days from the date of emergence to last oviposition was 17.85, 

 maximum 26, and minimum 10. 



According to this table the first eggs were deposited July 13 by 

 moths that emerged July 12 and the last eggs were laid September 

 12. A few moths issued July 10 and 11 from the Hamilton orchard 

 material, and, in addition to these, several moths emerged from 

 insectary-bred and other material as early as July 7. These moths 

 were confined together in a cage and deposited the earliest second- 

 brood eggs on July 11, as shown in figure 8, page 31. 



Length of life of moths. — Table XVII includes the summary of 

 records of the length of life of 1.719 male and female moths of the 

 first brood. The data in this table show that the average length of 

 life of 769 male moths was 11.86 days, of 950 female moths 12.68 

 days ; the maximum length of life of male moths 41 days, of female 

 moths 35 days; the minimum length of life of male moths 1 day. 

 of female moths 1 day. As has been frequently observed in other 

 studies of the life history of the codling moth with but few excep- 

 tions, the average life of the female moth is longer than that of the 

 male. 



