THE GRAPE-BEKKY MOTH, 



45 



that of the first brood. (See Tables IV and XII.) The larval stage 

 of this brood is also longer than that of the first brood, the average 

 being 22 days for the first brood of larvae as against 40 days for the 

 larvae of the second brood. The larvae of the second brood com- 

 mence to leave the fruit about the middle of September. The 

 maximum number of larVae leave the fruit during the last week in 

 September and the first 10 days in October. By October 15 the 

 number of larvae found in the fruit upon the vines is very small. By 

 this date practically all of them have dropped to the ground and 

 formed pupal cases on the small percentage of grape leaves that 

 have fallen prematurely from the vines. Rarely is a pupal case 

 of this second brood found on the leaves attached to the vines. On 



Fig. 15.— Seasonal history of the grape-berry moth as observed in 1909, at North East, Pa. (Original.) 



the moist leaves on the ground beneath the vines the second-brood 

 arvae and also a small percentage of the first brood make their 

 cocoons and pass the winter as pupae. 



PARASITIC ENEMIES. 



Detailed studies of the habits and life history of the grape-berry 

 moth during the past few years have shown that this insect is beset 

 with a large number of hymenopterous parasites. Previous to the 

 study of the habits of this pest made by Prof. M. V. Slingerland in 

 the vineyards of Chautauqua County, N. Y., the only record of 

 attack by parasites found in the literature on this subject is made by 

 Dr. C. V. Riley in 1869. Two maggots were found by him destroying 



