1-1 3/8" (25-35 mm). Above, FW patterned with small but conspicuous glassy dots, pattern obscured by long gray hair on male FW. HW above plain; light or dark brown
with rows of understated black markings and rows of pale brown or buff spots. Below, similar but less strongly marked. Female lighter, more marked.
Wild Indigo and Columbine duskywings best separated by host plants
. In Southwest, Afranius Duskywing has whitish fringes but farther north is very similar, and cannot be separated in field. Pacuvius may have more distinct marks.
Egg changes from green to pinkish before hatching. Mature caterpillar hairy, light green with white specks, and red, yellow, or orange had; overwinters. Chrysalis dark green or brownish. Host plant is probably lupine (Lupinus) in East, definitely golden banner (Thermopsis) in West; old records for willows (Salix) and poplars (Populus) are doubtful.
1 brood: April-June in East, later in Alaska, July in Rockies. 2 broods in California; March-September.
In East, generally mountainous sites such as willow swamps and sandy aspen flats; an array of habitats farther west.
Alaska to Maritimes, south in mountains to central California, Arizona, New Mexico, and Tennessee.
An uncommon, sparsely distributed butterfly in the eastern portion of its range, the Persius Duskywing is more common in the West. It is enormously versatile, yet usually quite uniform in appearance. The similar Afranius Duskywing (E. afranius) is somewhat lighter but lacks the hairy fore wings of the Persius. Some populations, especially in the Southwest, have white-tipped fringes. The Afranius Duskywing's caterpillars feed on lupine (Lupinus), lotus (Lotus), and other legumes. It flies from Alberta to Mexico