Northern Prairie Wildlife Research Center
Females are wingless. The male wingspan is 2.9 cm. Forewing is solid dark gray to pale cream with fine dark lines. This geometrid is common and widely distributed in western North America. Moths fly in late fall and winter. Caterpillars are generalist feeders on the foliage of flowering trees and shrubs, such as maple (Acer), oak (Quercus), cherry (Prunus), and rose (Rosa).
Similar species: Operophtera danbyi is larger, wings more elongate; species of Venusia, such as Venusia pearsalli, are smaller and fly in spring and late summer.