Aphids Injurious to Orchard Fruits, Etc. 29 
more or less reddish color, evident some distance away. When the 
plants are badly infested these leaves fall and the fruit becomes poor 
and ripens prematurely. Red currants are most subject to attack, 
but black currants and gooseberries also are injured. 
Fig. 22.—The variable peach aphis: Work on peach. (Essig.) 
The stem-mothers of the species are green, the other wingless 
forms (fig. 23, a) a yellowish green, while the winged ones have a 
black head and body and a large black patch on the abdomen. The 
eges are polished black. 
SEASONAL HISTORY. 
The stem-mothers hatch from the eggs in the early spring soon 
after the leaves open. After completing their growth they produce 
young aphids which infest the lower surface of the leaves. Some of 
the offspring of the stem-mother are winged and these fly tc moth er- 
