PROCEEDINGS, 1915. 



17 



Attempts were made throughout the summer, to transfer plaintain 

 forms to apple, and vice versa. Most of these failed. In one case, how- 

 ever, where fourth generation young from the apple, the progeny of a 

 wingless viviparous female, were placed on the apple, they came to matur- 

 ity and produced young that developed into ordinary plantain forms. 



The rosy aphis has a maximum of nine and a minimum of six genera- 

 tions in Nova Scotia. Most of the details concerning generations, num- 

 bers, etc., are shown in Fig. 2, and Tables 4, 5, 6, 7, & 8. 



Fig. 2. Generations of Aphis Sorbi Kalt., 1915. 



TABLE 4. 

 DURATION OF NYMPHAL STAGES OF APHIS SORBI. 



