Northern Prairie Wildlife Research Center
Wingspan 3.4 cm. Forewing is slightly falcate, yellow with narrow basal and median lines, pink-red in the postmedian areas. This geometrid is common and widely distributed in wet conifer forests of western North America. Moths fly in midsummer. Caterpillars feed on the foliage of red alder (Alnus rubra).
Similar species: Sicya morsicaria forewing is pale red-brown, speckled with black, hindwing is white, occurs in the Pacific West and through the southern Rocky Mountains, caterpillars feed on broad-leaf mistletoe (Phoradendron).