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 the female is small and yellowish. 
Fig. 4. 
Green Apple Aphis Oviparous Females and Males on Apple Twig 
—Del. Ex. Sta. 
