Northern Prairie Wildlife Research Center
Wingspan 3.1 cm. Forewing is light brown with a black median dash and black, dentate subanal spot; hindwing is brown. This noctuid is common and widely distributed in western North America, particularly common in wet coastal forests. Moths fly in midsummer. Caterpillars feed on the foliage of grasses and sedges.
Similar species: Oligia illocata is larger, forewing is dark brown with a large white reniform spot, abundant in wet coastal forests and in wet conifer forests of the northern Rocky Mountains, moths fly in fall, caterpillars feed on the foliage of alder (Alnus); Oligia tonsa is much smaller, forewing bicolored in black basally and pale gray distally, widely distributed; Oligia violacea forewing is mottled purple and lavender with yellow discal spots, hindwing white, widely distributed in dry forests; Oligia marina forewing is mottled black with a green tinge, occurs in dry forests of California and southwest Oregon; Euplexia benesimilis (Noctuidae) forewing is black with a pale brown postmedian band and a narrow white reniform spot, common in wet coastal forests.