August, '21] 



frost: late apple feeders 



327 



The latter curve is not absolutely comparable with the other curves 

 because it represents the percentage of fruits while the other curves 

 are the percentages of injuries. Hence we find that the curve for un- 



PIRCENTAOE OF LEAF ROLLER INJURY 

 Arendtavllle.Pa. 1920. 



Dneound fruit 

 In Check plat. 



af-roller Injury 



Chtolc Flat 



leaf-roller Injury 

 in Duetea Plat. 



Leaf-roller Injury 

 In Sprayed Plat. 



9 jui^ 



9 AUGUST . 



14 SEPT . 



sound fruit drops below the curve for Leaf-roller Injury in the Check 

 on July 9th. The three high points of the Leaf- roller curve are indic- 

 ative of the three generations of the Leaf -roller, Eulia veluitnana Walk., 



OHART ILLUSTRATING THE NUMBER AND' OVERLAPPING OP GENERATIONS 

 OF Bulla velutlnana Walk. 



MAY. 



JUNE, 



JULY. 



AUG. 



SEPT. 



OCT. 



NOV. 



which caused the injury and is shown on the chart illustrating the num- 

 ber and overlapping of generations of this species. The curves for 

 the Sprayed and Dusted plats indicate a considerable reduction in per- 



