12 



BULLETIN 911, U. S. DEPARTMENT OE AGRICULTURE. 



FIRST GENERATION. 



INCUBATION PERIOD OF FIRST-BROOD EGGS. 



Table XV. — Incubation period of first-brood eggs of the grape-berry moth, Sandusky, 



Ohio, 1917. 



Date of oviposition. 



Date of 

 hatching. 



Number 

 oflarvse. 



Incuba- 

 tion 

 period 

 (in days). 





June 28 

 July 4 

 July 5 

 July 6 

 July 8 

 July 5 

 July 6 

 July 7 

 July 6 

 July 7 

 July 24 

 July 25 

 July 26 

 July 28 

 July 28 

 July 30 

 July 29 

 July 30 

 July 30 

 July 3i 



4 



28 



18 



8 



1 



24 







2 



18 



2 



1 



2 



1 



1 



2 



4 



2 



3 



27 



11 



7 



30 



4 



30... 



5 



30. 



6 



30 



8 



July 1 



4 



1... .. . 



5 



1 



6 



1 



4 



1 



5 



21 



3 



22 



3 



23 



3 



23 : 





24 



4 



24 



6 



26 



3 



26 



4 



26 



4 



27 



4 







Total 



165 











Average length of incubation period, 4.39 days. 

 Maximum length of incubation period, 8 days. 

 Minimum length of incubation period, 3 days. 



LENGTH OF FEEDING PERIOD OF FIRST-BROOD LARV2E. 



Records from the date of hatching until date of leaving fruit were 

 secured on 70 larvae in the insectary. 



Table XVI. — Length of feeding period of 70 first-brood larvss of the grape-berry moth in 

 grapes in rearing jars in the insectary, Sandusky, Ohio, 1917. 



Number oflarvae. 



Larvfe 

 hatched. 



LarviB 

 left fruit. 



Feeding 

 period. 



i Number of larvae. 



i 



Larvre 

 hatched. 



Larvse 

 left fruit. 



Feed- 

 ing 



period. 



2. 



July 3 

 ...do 



July 21 

 July 25 

 July 26 

 July 29 

 July 30 

 Aug. 5 

 July 19 

 July 21 

 July 22 

 July 23 

 July 24 

 July 27 

 July 28 

 July 29 

 Aug. 5 

 July 19 

 July 20 

 July 21 

 July 22 

 July 23 

 July 24 



Days. 

 18 

 22 

 23 

 26 

 27 

 33 

 15 

 17 

 18 

 19 

 20 

 23 

 24 

 25 

 32 

 14 

 15 

 16 

 17 

 18 

 19 



2 



July 5 



July 25 

 July 28 

 July 29 

 July 31 

 Aug. 1 

 Aug. 2 

 Aug. 6 

 July 22 

 July 23 

 July 26 

 July 27 

 July 30 

 July 31 

 Aug. 1 

 Aug. 2 

 Aug. 12 

 July 21 

 July 25 



Days. 

 20 



2. 



1. . 



23 



1 



.do 



2. 



July 5 

 . ..do 



24 



1. 



...do 



1 



26 



1. 



...do 



1... 



...do 



27 



1. 



...do 



1... 



...do 



28 



2. 



July 4 

 .do 



2 



...do 



32 



3 



3. 



July 6 

 ...do 



16 



2. 



...do 



6 



17 



6. 



...do 



1. . 



...do 



20 



2. 



.do 



1. 



...do 



21 



1. 



...do 



1. 



...do 



24 



1. 



...do 



1... 



...do 



25 



2. 



. .do 



1. .. 



...do 



26 



1. 



.do 



1. 



...do 



27 



1. 



July 5 

 ...do 



1. 



...do 



37 



1. 



1 



July 7 



14 



3. 



...do 



1 



18 



4 



...do 



70 







3.. 



...do 





2 



...do 











Average days, 20.62. 

 Maximum days, 37. 

 Minimum days, 14. 



