Ipimorpha nanaimo is a medium sized, light yellow orange Noctuid moth with large orbicular, reniform, and claviform spots which are filled with scales slightly darker than the ground color. The postmedial and antemedial lines are fairly straight and darker than the ground color, with a paler, yellowish component outside the median area. It flies west of the Cascades, mostly in lower elevation riparian corridors, from late summer into early fall. Larval hosts include willows, but Populus trichocarpa (Black Cottonwood) may be the preferred host.
I. viridipallida is similar, and is occasionally found on the westside. It is paler, with a greenish tint, and its hindwing is paler and lacks the postmedial line of I. nanaimo. I. pleonectusa flies at higher elevations and east of the Cascades, is overall darker, and has pale postmedial and antemedial lines. Cosmia calami is most similar in size and color, but it lacks a claviform spot, and the orbicular and reniform spots are much smaller.
Size- FW length 14-17mm
Habitat- Riparian corridors
Range- West of the Cascades
Eats- Larval hosts are Salix spp, and Populus spp, particularly P. trichocarpa
Flight Season- July to October