Pacific Northwest Moths

Identification

Adults

Cucullia omissa is a large, narrow-winged moth (FW length 20 - 22 mm) that flies in forests throughout much of our region during the summer. It has a smooth, medium blue-gray forewing with a brown costa and clustered black marks near the anal angle.  As in other Cucullia, the forewing has a convex distal costal margin and a pointed apex, and the patagiae can be raised into a pointed "hood" when the moth is resting, which is variably present in pinned specimens. The forewing ground color is smooth medium-dark violet-gray. The costa and trailing margin of dark gray-brown and slightly reddish brown. The veins are dark, very thin, and a similar thin basal dash is present. A few gray lines are present between the veins near the outer margin. Two stronger black dashes are present at the anal angle, longest near vein CuA2, with red-brown between them. An adjacent C-shaped double black mark preceded by a dark smudge represents a remnant of the postmedial line on the trailing margin. Traces of the gray antemedial line are barely evident on the mid-wing in a few specimens, but the vague gray or brown outlines of the orbicular and reniform spots are usually visible. The terminal line is a series of black lines between the veins on most of the wings, becoming a continuous line near the anal angle. The hindwing is pale brown-gray, broadly darker brown-gray at the margin, with dark gray veins and thin terminal line. The hindwing fringe is white with a light tan and gray fringe.

This species can be recognized from other Cucullia species by the smooth purplish gray and dark brown forewing lacking distinct marks other than the black dashes and postmedial line remnants on the lateral trailing margin. The most similar species is Cucullia postera which has a more streaky forewing with similar color and pattern.

Habitat

This species is widely distributed across Canada in open areas of cool, moist forests.  In our area this includes open meadows and roadsides at high elevations in the Cascades and Rocky Mountains, and in coastal rainforests west of the Cascades.  It is usually rare and sporadic in the Pacific Northwest.

Distribution

Pacific Northwest

Cucullia omissa is found in forests on both sides of the Cascade Range as far north as southern British Columbia in our region. It appears to be more common in British Columbia and forests in the eastern part of the region than in the Cascades or further west.

Global

This species has a transcontinental range, occurring in a relatively narrow north-south distribution near the Canada-United States border to New England and Newfoundland. The range extends south to Kentucky in the Appalachian Mountains and Colorado, Utah, and northeastern Nevada in the Rocky Mountains. It also occurs in northern California.

Life History

Larvae

This species is a foodplant specialist feeding on asters (Aster spp.) in the Asteraceae.

Adults

This species flies during the summer, usually in from May to early August. It is attracted to lights, but possibly less strongly than many other moths.

Economic Importance

None.

Literature

BugGuide

Moth Photographers Group

Poole (1995)

Poole (neartica.com)