20 Farmers’ Bulletin 1128. 
They then give birth to young, and these when grown produce others 
until the leaves are often thickly covered with the insects. Winged 
forms develop toward late spring and continue to appear until late 
midsummer or later. These winged forms migrate to certain grasses 
and produce numerous generations during the summer. In the fall 
return migrants are produced, which give birth to the egg-laying 
forms on the plums. These migrants first appear in early Septem- 
ber, but continue to arrive until late October or early November. 
THE HAWKWEED APHIS.' 
The hawkweed aphis is a native of Europe, where it lives on plums. 
In India it is very injurious to peaches and is there known as the 
peach-curl aphis. It has recently been 
found in numbers in our western region 
on plums. The winged forms have a 
black head and thorax and a green abdo- 
men with a large black patch on it. 
The honey tubes are short. The wingless 
forms are green. (Fig. 12.) 
SEASONAL HISTORY. 
The eggs are laid upon plum trees and 
in the spring hatch to the greenish 
stem-mothers. These produce wingless 
forms and in late spring the winged ones 
may be found. These winged ones mi- 
grate to hawkweed,  scorpion-grass, 
groundsel, etc., and produce summer 
Fic. 12.—The hawkweed aphis: a, Wing- colonies ye these plants. In the fall 
less form from plums; b, cornicles of winged migrants return to the plums 
the spring migrant; c, antenna of sum- : : : 
mer winged form; d, antenna of spring and deposit the wingless egg-laying 
migrant; ¢, cornicle of summer wing- females. ‘The winged males follow and 
less form; /, cornicle of spring wingless ; : 
form. a, Muchenlarged; b-/, moreen- mating takes place on the plums, 
ears peaches, etc. In this country the insect 
has not been found to be injurious to peaches, but it may become 
so in time. 
CHERRY APHIDS. 
THE BLACK CHERRY APHIS.? 
The black cherry aphis is an abundant species almost everywhere 
upon cherry trees. The wingless insects have a rounded abdomen, 
which gives them a more or less globular appearance. Both wing- 
less and winged forms are shining deep brown to black, while the 
1 Anuraphis helichrysi (Kalt.). 2 Myzus cerasi (Fab.). 
