48 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



them. When full grown the stem-mother 

 is purplish-gray covered with a sparse 

 white bloom and is almost as broad as 

 long. The lice of the third generation 

 are full grown in early June and are 

 all winged pinkish individuals. They 



migrate in a body to an alternate host- 

 plant, as yet unknown. In the fall a 

 generation of migrants return to the 

 apple and give birth to the true sexes. 

 Of these the male is black and winged 

 while thp fpmale if small and ypllowish. 



Fig. 4. Green Apple Aphis Ovipai-ous Females and Males on Apple Twig 



— Del. Ex. Sta. 



