This species contains many subspecies. P. mercurius is found from Arizona, Texas, and Florida, south through Mexico, the West Indies and Central America to Argentina. In the subtropics it lives near streams in moist, lowland tropical forests, where it is especially associated with edges and openings. In Peru it is also found in the highlands.|
Its upperside is dark brown to black with golden orange near the wing base, and four small, white spots on the forewings. Underside is chestnut brown with white frosting on the outer edges. Wingspan is 58-70mm. Larvae are olive green or honey colored with a dark reddish-brown head and red eyespots, dark brown mottling, with brown transverse bands, and red lateral stripes. Larvae are night feeders and live in leaf nests. In Latin America foodplants are trees and vines of the Bean family (Fabaceae). Adults sip flower nectar and mud, bask with their wings spread open, and males perch to find females. A similar species is Epargyreus exodeus (Exodeus Skipper).