1 3/8-1 7/8" (35-48 mm). Male dull orange above with dark borders and dusky scaling near body. Female dull orange or yellowish above, often nearly completely covered with dusky scaling. Both sexes have pink fringe and red-orange HW cell spot above. Below, green- to olive-yellow with black FW cell spot and elongated HW cell spot, silver- and pink-edged.
Mead's Sulphur is deeper, brighter orange above, greener below. Orange form Queen Alexandra's Sulphur has larger wing base above. Orange Sulphur has brown spots on HW below.
Caterpillar green and laterally striped; it or chrysalis may overwinter; possibly takes 2 years to mature. Alpine milkvetch (Astragalus alpinus) is recorded host plant.
Late June-early August.
Arctic tundra and grassy slopes and swales.
Circumpolar. High Arctic Eurasia and North America including Baffin Island and Greenland, south along Hudson Bay to Churchill; in mountains to mid-Alberta and N. British Columbia.
Truly holarctic, this butterfly skirts the Arctic Circle around the globe. It is one of only about half a dozen butterflies resident in Greenland. Living on the margins of human habitability, it flits quickly and low over the tussocks and lichen-encrusted stones of the Northland.