Northern Prairie Wildlife Research Center
Wingspan 2.8 cm. Forewing is pale mottled brown with three narrow dark lines, forewing and hindwing with smooth margins. This geometrid is abundant in oak woodlands in the Pacific West. Moths fly in summer. Caterpillars feed on the foliage of oak (Quercus).
Similar species: S. respersata serves to represent a large group of over 30 similar species of Semiothisa that are widely distributed in western North America, many of these species utilize different caterpillar food plants. Some of the more common species include Semiothisa setonana on juniper (Juniperus); Semiothisa burneyata on Cupressaceae, particularly incense cedar (Calocedrus decurrens) and western red cedar (Thuja plicata); Semiothisa denticulata on Rosaceae; and Semiothisa neptaria on Salicaceae; Itame colata with a brown postmedian band.