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"Labial palpi silvery white. Head silvery white; forehead and face faintly tinged with pale golden brown. Antennae silvery, annulated with dark brown. Fore wings silvery white, with a pale golden brown streak at the base of costa. About the middle of the wing is an oblique, dark golden brown band, broadest on the inner margin, and tapering to the costa, beyond which is a narrower, oblique band of the same hue produced in the middle, as a rather broad, somewhat curved streak toward the tip, behind which it is arrested; cilia pale golden brown, with a darker hinder-marginal line; hind wings dark gray; cilia the same. / Another specimen, on the middle of the inner margin, has a rectangular, golden brown patch, not extended to the costa, with an irregular, obliquely placed patch of the same hue on the inner margin, near the tip, and slightly connected with a small costal patch placed midway between the patches, on the inner margin. The tip of the wing is golden brown, and is scarcely connected with the second patch by a posteriorly produced portion" (Clemens, 1861: 7). Busck (1907: 14) provided a thorough description of the species, indicating "Alar expanse: 13 mm., Thorax white ... Forewing with veins 7 [R4] and 8 [R5] separate... different from the European A. andereggiella". Forbes (1923: 346) also gave a description, indicating that the wingspread could vary from 10 to 13 mm. A closely related species to A. oreasella in Alberta is A. goedartella which has much denser golden stripping on its forewing. Otherwise, A. oreasella can be easily identified by its typical forewing pattern.

This species overwinters as an egg on leaf buds. The full-fed light green caterpillar is 7 mm long. It tunnel into young shoots of its food plant, Choke cherry and Pin cherry, in May; it then exits the stem, and pupates. During late May or early June, new green shoots wither and die. It is usually easy to find them by looking for a small hole at the base of the stem and cut open, then look for light a green caterpillar.

In the United States, it is recorded from New York (Forbes 1923: 346), Michigan (Nielsen 1998: 7), Idaho, Missouri, Colorado, New Mexico (Busck, 1907: 14-15), and California (Busck 1907: 14-15; Powell et al, 1998). In Canada, there are records from Valcartier, Quebec; Parry Sound, Ontario, Alberta (Prentice 1965: 792) and Saskatchewan and Manitoba. In Alberta, it has been collected near Edmonton, Hardisty, Lac La Biche and Vinca Bridge.