2-2 1/2" (51-63 mm). Large. Above, pale to bright tawny with darker, somewhat scalloped margins. Male has dark patches at base and along FW costa, on FW 1 or 2 small black eyespots with pupils; female lacks dark patch and has more and larger eyespots; both sexes usually have 1 eyespot on HW margin. Below, HW uniform barklike brown and gray striated, with darker, irregular median band in some populations; FW tawny.
Chryxus Arctic smaller, lighter, with a more prominent median band and less uniform striation on HW below.
Egg dirty-whitish, oblong, flat-topped. Caterpillar tan with black stripes along back, brown and whitish stripes along sides; feeds on grasses (Poaceae); takes 2 years to mature.
1 brood; late May-August. Normally only even years in North.
Forest clearings and roads, dry meadows and mountain slopes near forests, and canyons.
Vancouver and San Juan islands; British Columbia to California in Cascades and Coast Ranges.
Despite its Latin name and its alternate common name, this species has not recently appeared in Nevada. Great Arctic is a far more appropriate name, particularly since this butterfly is the largest western arctic. Vancouver Island populations are particularly large. Groups of adults, especially males, tend to fly to prominences, and in small forest glades males patrol their territory. The Great Arctic flies in mountain forests, on wooded bluffs, and on bar mountain summits near sea level, but not at all in arctic conditions. Near the Pacific its distribution is very spotty but is more continuous in the mountains.