Wing span: 7/8 - 1 1/8 inches (2.2 - 2.9 cm).

Identification: One narrow tail on hindwing. Upperside of male iridescent blue; summer females uniformly brown, spring females smaller with much blue at the wing bases. Underside of hindwing pale gray with black bar at end of cell, distinct black spots, and three large orange spots at outer margin near tail.

Life history: Males patrol near the host plants during daylight hours. Females lay eggs on flower buds; caterpillars eat buds, flowers, and seeds. The caterpillar hibernates, pupating the following spring. Although most Lycaenids do not perch with open wings, Eastern Tailed-Blues sometimes bask with their wings at a 45 angle.

Flight: Three broods from April-November in the north, many broods from February-November in the south.

Caterpillar hosts: Many plants in the pea family including yellow sweet clover (Melilotus officinalis), alfalfa (Medicago sativa); various species of vetch (Vicia), clover (Trifolium), wild pea (Lathyrus), and bush clover (Lespedeza); and others.

Adult food: This butterfly has a low flight and a short proboscis, thus is found at flowers close to the ground which are open or short-tubed. These include white sweet clover, shepherd's needle, wild strawberry, winter cress, cinquefoils, asters, and others.

Habitat: Many open, sunny places including weedy areas and disturbed habitats.

Range: Southeast Canada and Eastern United States west to western North Dakota, central Colorado, and central Texas. Also ranges from southeastern Arizona, western New Mexico, and west Texas south to Costa Rica.