THE CODLING MOTH IN THE YAKIMA VALLEY. 



41 



Number of eggs per female. — Of the 1,166 moths observed, 696 were 

 females, which deposited 13,763 eggs, or an average of 19.77, which 

 is the highest average for spring-brood moths recorded in Yakima. 

 These data are given in Table 34. 



Length of life of moths. — The average length of life of 495 male 

 moths was 12.29 days, of 723 females 13.85 days, or 1.56 days longer 

 than that of the males as shown in Table 35. The length of life of 

 these moths was less by several days than the life of spring-brood 

 moths in either 1919 or 1920. 



Table 35. 



-Length of life of male and female codling moths of the spring brood, 

 Yakima, Wash., 1921. 



Male. 



Female. 



Male. 



Female. 



Male. 



Female. 



Length 

 of life. 



Num- 

 ber of 

 moths. 



Length 

 of life. 



Num- 

 ber of. 

 moths. 



Length 

 of life. 



Num- 

 ber of 

 moths. 



Length 

 of life. 



Num- 

 ber of 

 moths. 



Length 

 of life. 



Num- 

 ber of 

 moths. 



Length 

 of life. 



Num- 

 ber of 

 moths. 



Days. 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 

 12 

 13 



4 

 4 

 7 

 11 

 22 

 43 

 42 

 45 

 54 

 37 

 22 

 19 



Days. 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 





 2 

 4 

 10 

 28 

 47 

 42 

 43 

 50 

 52 

 49 

 39 



Days. 

 14 

 15 

 16 

 17 

 18 

 1-9 

 20 

 21 

 22 

 23 

 24 

 25 



22 

 41 

 21 

 19 

 15 

 12 

 13 

 11 

 6 

 7 

 3 

 3 



Days. 

 14 

 ' 15 

 16 

 17 

 18" 

 19 

 20 

 21 

 22 

 23 

 24 

 25 



47 

 48 

 40 

 35 

 45 

 26 

 25 

 27 

 15 

 11 

 14 

 5 



Days. 

 26 

 27 

 28 

 29 

 30 

 31 

 32 

 33 

 34 

 35 



Total. 



2 

 3 

 2 

 2 

 2 

 

 

 1 

 

 



Days. 

 26 

 27 

 28 

 29 

 30 

 31 

 32 

 33 

 34 

 35 



Total. 



7 

 4 

 4 

 2 

 

 1 

 

 

 



1 



495 



723 



Average length of life of male moths, 12.29 days; female moths, 13.85 da] 

 Maximum length of life of male moths, 33 days; female moths, 35 days." 

 Minimum length of life of male moths, 2 days; female moths, 2 days. 



THE FIRST GENERATION. 



EGGS OF THE FIRST BROOD. 



Time of egg deposition. — In Figure 25 is given the time of deposi- 

 tion of 14,822 eggs of the first brood. The first eggs were laid on 

 May 23 and the last June 30, covering a period of over five weeks. 

 Mean temperatures above 70° F. for the 6-hour period between 3 and 

 9 p.m., commencing May 29 and ending June 8, encouraged the moths 

 to deposit 11,390 eggs, or 76.85 per cent of the total number of eggs 

 during these 11 days. The maximum number of eggs laid in a single 

 day was 1,379 on June 4. 



Length of incubation. — Embryological studies of 7,999 eggs of the 

 first brood show the average number of days from deposition to the 

 appearance of the red ring to be 3.45; average number of days 

 from deposition to the appearance of the black spot 7.6 days, and the 

 average length of the incubation period 9.31 days. These intervals 

 are shorter than the corresponding intervals recorded for 1919 and 

 1920. These data are found in Table 36. 



