Northern Prairie Wildlife Research Center
Wingspan 3.7 cm. Forewing is slightly falcate, gray to yellow-tan with narrow black postmedian and basal lines edged with orange and a small black discal spot. This geometrid is common and widely distributed in western North America. Moths fly in fall. Caterpillars are generalist feeders on the foliage of flowering trees and shrubs, in particular oak (Quercus).
Similar species: Metarranthis duaria (Geometridae) has purple-brown wings and flies in early spring, most common in the Pacific West.