Northern Prairie Wildlife Research Center
Wingspan 5.0 cm. Forewing is white with large discal spots and submarginal spots outlined in black; hindwing is pale brown. This noctuid is abundant in wet coastal forests. Moths fly in midsummer. Caterpillars feed on the foliage of red alder (Alnus rubra).
Similar species: Polia discalis forewing is pale gray with obscure markings, widely distributed in wet conifer forests of western North America, caterpillars are generalist feeders on the foliage of flowering trees and shrubs; Lasionycta wyatti (Noctuidae) is smaller and confined to coastal sand dunes.