Image Credit: Brad Smith
Identification: Upper side of male iridescent silvery blue with narrow dark borders; female darker blue with wide borders. Both sexes have white fringe. Underside gray-brown; both wings with row of white-ringed, round black spots. Subspecies xerces (Boisduval) and pseudoxerces Emmel and Emmel have large white spots with or without black centers.
Wing Span: 7/8 - 1 1/4 inches (2.2 - 3.2 cm).
Caterpillar Hosts: Astragalus, Lotus, Lupinus, Melilotus, Oxytropis, Lathyrus, Vicia, and other species in the pea family.
Adult Food: Nectar from flowers including Asteraceae.
Habitat: A variety of locations including open woods, coastal dunes, prairies, meadows, road edges, rocky moist woods, and brushy fields.
http://www.butterfliesandmoths.org/species/Glaucopsyche-lygdamus