Aphids Injurious to Orchard Fruits, Etc. 91 
color of the young ranges from amber through various shades of 
brown. The young stem-mothers are deep greenish. 
On account of their early hatching in spring the young stem- 
mothers do not find leaf food available. They therefore attack 
the buds even before these show any signs of bursting. Sometimes 
F 1G. 13.—The black cherry aphis: Curled terminal cherry leaves following attack by this species. 
the stem-mothers will feed in this manner for nearly a week before 
the buds begin to open. As soon as the leaves are formed the young 
insects attack them and cause them to curl. As they spread from 
leaf to leaf a large and conspicuous cluster of curled-up leaves (fig. 
13) is formed, within which the insects feed. 
SEASONAL HISTORY. 
The eggs are laid upon the cherry twigs in the fall and hatch 
early in the spring. The insects are able to withstand freezing 
