LIBRARY

332
COLLEGE ENTOMOLOGY
posed of groups of three or more ocelli or large, hemispherical, and faceted; and
without or with a posterior terete tubercle. Ocelli, three, present in the winged
forms only (but present also in some apterous males). Rostrum well developed,
short or longer than the body, three- to four-segmented; setre or piercing
lancets very long. Thorax well developed and distinct in alates or winged forms
and more or less fused with the abdomen in the apterous forms; pronotum
Fld. 114. Characters of APHIDIDlE or plant lice. A, winged migrant of Macrosiphum
scoliopi Essig; B, sexual female of the bamboo aphid, Myz()callis arundinari;s Essig; C, sexual
female of the maple aphid, Drepanosiphllm acerijolii (Thomas).
usually distinguishable and in alates may have a pair of lateral tubercles; proand
metathoracic spiracles. Wings present on migrants and certain sexuales,
usually males; normally as long as or longer than body; thin and transparent
or partly clouded; few-veined; hind pair much smaller, with fewer veins, and
bearing hamuli; folded roof-like or rarely flat over the back. Legs short or
long and rather slender; often hairy; tibire of sexual females often swollen and
with numerous sensoria-like areas; tarsi usually two-segmented with basal
segment small, rarely one-segmented or absent; claws, one pair, simple, without
aralia. Abdomen indistinctly segmented and with eight or nine segments at
most; wax glands, lateral and dorsal tubercles, and hairs or setre usually present,