27 
THE CHERRY APHIS. 
( Myzus cerasi: Fabr.) 
This aphis often causes the leaves of the cherry to become crumpled 
and rolled, and on young trees sometimes does serious damage. The 
winged and wingless insects are both of a dark brown color, and look 
much like the black peach aphis. The eggs are laid in the fall on 
the branches at the base of buds and in crevices of the bark. The 
young hatch from them in the spring when the buds begin to swell, 
crawl out upon the buds and growing leaves, and develop into stem- 
mothers, which give birth to living young. This is kept up all sum- 
mer until the fall, when the sexes appear and the female deposits her 
eggs. A number of winged migrants are developed in the spring 
generations, which serve to spread the species. The insects usually 
become very abundant by June, but in midsummer they are not as 
common. 
FAMILY PSYLLIDZ. 
THE PEAR-TREE PSYLLA. 
( Psylla pyricola Forster—fig. 17.) 
This insect is closely related to the plant-lice, but readily known by 
its longer antenne and its ability to hop. Its color is reddish, with 
5 . 
Fig. 17.—Psylla pyricola; greatly enlarged. (Marlatt.) 
some black markings, and with clear wings laid roof-like over the 
body. When disturbed, it hops and flies away. 
