|scientific name Euxoa silens |
The only Alberta specimen was collected June 18, earlier than most Euxoa.
A relatively large Euxoa (3.7-4.1 cm wingspan). Forewings variable, in both a strongly contrasting pattern or a very plain one. Ground a light blue-grey, with the costa in particular usually pale and contrasting with the rest of the forewing. A black basal streak runs into a broader dark median streak below the costa, and encompassing the small oval grey orbicular and larger kidney-shaped reniform spots. Terminal area and fringe darker grey brown. Hindwing of males white shaded with dark scales along the outer margin, female sooty brown, shading darker on the outer half. In plain specimens, the forewings lack the dark streaks and contrasting dark shading except in the terminal area of the forewing. Lafontaine (1987) provides illustrations of both forms, illustrations of the genitalia and a key.
Very little is known. There is a single annual brood. Adults are attracted to light. The immature stages are unknown.
Apparently rare in Alberta (one record), which is at the extreme northeastern edge of the range.
Like most Euxoa species, the larvae are likely generalists on a variety of herbs.
Euxoa silens is a western species most abundant in the deserts of the intermountain area from southern BC south to southern California and central Arizona, west to western Colorado and southwestern Montana. The single Alberta collection is from Lethbridge.
This is yet another western moth that barely reaches Alberta in the southwest corner of the province. It must be very rare here, as only the single specimen was collected at Lethbridge, in spite of having run light traps there since the 1920's.
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