24 



BULLETIN 911, IT. S. DEPABTMEN/T OF AGBICULTUBE. 



SEASONAL-HISTORY STUDIES, 1918. 



SPRING BROOD. 



TIME OF EMERGENCE AND SEX OF MOTHS OF THE SPRING BROOD. 



Table XXVII shows the dates of emergence of spring-brood moths 

 and the number of each sex that emerged each day. 



Tabie XXVII. — Time of emergence and sex of moths of the spring brood of the grape- 

 berry moth, Sandusky, Ohio, 1918. 



Date of 



Number of moths. 



Mean 

 daily 

 temper- 

 ature. 



Date of 

 emer- 

 gence. 



Number of moths. 



Mean 

 daily 



gence. 



S 



? 



§ 



Total. 



(? 



9 



§ 



Total. 



temper- 

 ature. 



May 22 

 25 

 26 

 27 

 28 

 29 

 30 

 31 



June 1 

 2 



3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 

 12 

 13 

 14 

 15 

 16 



1 

 1 

 

 



1 



4 

 3 

 2 

 12 

 12 

 14 

 6 

 9 

 12 

 4 

 5 

 10 

 10 

 5 

 7 

 2 

 6 

 3 

 4 







1 

 4 

 4 

 5 

 3 

 13 

 16 

 10 

 36 

 36 

 42 

 25 

 29 

 36 

 21 

 11 

 36 

 30 

 12 

 38 

 14 

 29 

 11 

 12 



74 

 72 

 78 

 78 

 66 

 64 

 72 

 78 

 81 

 75 

 68 

 74 

 67 

 73 

 66 

 64 

 69 

 66 

 70 

 72 

 62 

 66 

 64 

 72 



June 17 



18 



19 



20 



21 



23 



24 



25 



26 



27 



28 



29 



30 



July 1 



2 



3 



4 



5 



6 



7 



9 



12 



Total . . . 



8 

 3 

 2 

 1 

 2 



1 

 4 



1 

 2 

 3 



1 



26 

 16 

 6 

 6 

 14 

 12 

 13 

 10 

 11 

 7 

 S 

 13 

 8 

 4 

 1 

 2 

 2 

 2 

 2 

 4 

 1 

 1 



1 



1 



1 

 1 

 2 



1 



2 



1 



34 

 19 

 9 

 7 



16 



12 



15 



14 



12 



9 



12 



16 



8 



4 



1 



3 



5 



2 



3 



4 



1 



1 



70 



3 



2 



4 



2 



9 



11 



6 



21 



17 



26 



17 



20 



22 



17 



6 



25 



20 



6 



30 



12 



22 



8 



7 



2 

 1 



2 

 2 

 3 

 7 

 2 

 2 



2. 



1 



1 



1 



1 

 1 



65 

 66 

 61 

 70 

 62 

 66 

 66 

 66 

 76 

 74 

 74 

 75 

 62 

 62 

 72 

 73 

 76 

 72 

 63 

 64 

 66 



161 



482 



38 



681 





The early opening of the season hastened the grape growth and 

 moth emergence was correspondingly early. The first emergence 

 took place on May 22 and emergence in considerable numbers began 

 on June 1. A rather high rate of emergence prevailed for about a 

 two-week period and then gradually subsided. (Fig. 4.) 



PROPORTION OF SEXES OF MOTHS OF THE SPRING BROOD. 



Table XXVIII. — Proportion of sexes of moths of spring brood of the grape-berry moth, 



Sandusky, Ohio, 1918. 



Sex of moths. 



Number 

 of moths. 



Percent- 

 age of 

 sexes. 



Male. 





161 

 482 

 38 



25. 04 





74.96 













Total 



681 



100. 00 









The proportions as shown in Table XXVIII are comparable with 

 the figures in Table XI on the spring brood of moths in 1917. It 

 appears that the preponderance of females is the usual condition. 



