Wild Indigo Duskywing
1 1/8-1 5/8" (21-41 mm). FW patterned above, dark chocolate brown on inner part, outer part purplish to light brown with darker markings and lighter bands; glassy spots near FW tips; pale brown patch between spots and dark base of wing. HW brown with lighter patches. Fringes brown. Below, similar to upperside with fainter markings.
Zarucco Duskywing has pale brown patch and large HW. Columbine Duskywing smaller. Persius Duskywing best separated by host plant.
Egg green at first, becoming pinkish. Young caterpillar orange-white; overwinters. Fully grown caterpillar hairy, light green with white specks, and red, yellow, or orange patterned head. Chrysalis dark green or brownish. Host plant is probably lupine (Lupinus) in East, definitely gold 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.