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there the females give birth to a generation of wingless sexual females (B), which, when mature, mate with the males and produce the winter eggs. The third of the aphid species that infest the spring buds of the apple is known as the apple-grain aphis, so called because, being a migratory species like the rosy

A

F*. *oo. The winged male(A) and the wingless sexual female (B) of the rosy apple aphis

aphis, it spends the summer upon the leaves of grains and grasses. The eggs of the apple-grain aphis are usually the first to hatch in the spring, and the young aphids of this species (Fig. 95 A) are distinguished by their very dark green color, which gives them a blackish appear- ance when massed upon the buds. Later they spread to the older leaves and to the petals of the apple blossoms, but on the whole their damage to the apple trees is less than that of either of the other two species. The summer history of the apple-grain aphids is similar to that of the rosy aphis, excepting that they make their summer home on grains and grasses instead of on plantains. In the fall, the winged female migrants (Plate 4) come back to the apple and there give birth to wingless sexual females, which are later sought out by the winged males. It would be impossible here even to enumerate the

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