Northern Prairie Wildlife Research Center
Wingspan 2.8 cm. Forewing with falcate apex, pale yellow or brown with two narrow lines and three black marks in the submarginal area. This geometrid is common and widely distributed in wet forests of the Pacific Northwest. Moths fly in late summer. Caterpillars feed on the foliage of alder (Alnus), aspen (Populus), and willow (Salix).
Similar species: Elpiste metanemaria lacks the sharply defined markings on the forewing and is limited to coastal forests of Oregon and California; some species, other than those discussed herein, of Itame and Semiothisa are similar but lack the three submarginal spots of E. lorquinaria.