Northern Prairie Wildlife Research Center
Wingspan 4.4 cm. Forewing is a mottled dark gray to black-gray with fine dark longitudinal lines. This notodontid is common in wet forests and widely distributed in western North America. Moths fly from early spring to early summer. Caterpillars feed on the foliage of willows (Salix) and poplars (Populus).
Similar species: Gluphisia septentrionis is smaller, forewing with a yellow to orange median band; Heterocampa lunata (Notodontidae) is larger, forewing is dark gray with few markings, hindwing white to pale gray, occurs in the Rocky Mountains; species of Dasychira forewing with a white subanal spot or white median patches on the forewing.