This name is proposed for a large species of Aphis which forms follicles on the leaves of the silver-leaved Maple (Acer eriocarpum). The specimens were sent to us by our ex-President, Caleb Cope, Esq. This curious Aphis appeal's to be a new species. Dr. Fitch, in the descriptions of the New York State Cabinet; mentions the European Aphis acres as occurring in New York, and may have this woolly species in view; but the description of the foreign one does not mention the remarkable filaments which approximate the insect to certain tropical forms. Both sexes are covered with white down, and have a bunch of white filaments posteriorly, some of which are three-fourths of an inch long, a character in which this species surpasses the Eriosoma of the apple tree. Male, - Black, feet long, slender, and rufous; tarsi bi-articulate; wings slightly deflexed, translucent, pale ferruginous at the base; submarginal nervure conspicuous, black, and ending in a long stigma; disc with four simple nervures; posterior wings with three nervures; mesonotum polished, with a deep Y-shaped impression; abdomen without tubes; promuscis obsolete; antennae 6 - articulate, the first two short, the 3d long; and the 4th, 5th, 6th, gradually lengthening; length of the body 1 1/2 lines, or to the end of the wings 2 1/2. Female and pupa. - Apterous, dark reddish brown, feet paler; promuscis twice as long as the head, thickened near the apex; length 1 1/2 lines.