Arcas is a genus of gossamer-wings in the butterfly family Lycaenidae. There are about six described species in Arcas, found in the Neotropics. The sister genus of Arcas is Theritas.
Species
These nine species belong to the genus Arcas:
Arcas alleluia Bálint, 2002 - eastern Peru
Arcas cypria (Geyer, 1837) - Mexico to Venezuela and Colombia
Arcas delphia Nicolay, 1971 - Costa Rica to western Ecuador
Arcas ducalis (Westwood, 1851) - Brazil
Arcas gozmanyi (Bálint, 2006) - Costa Rica to western Ecuador
Arcas imperialis (Cramer, 1775) - Mexico to Argentina and southern Brazil
Arcas jivaro Nicolay, 1971 - Ecuador to Bolivia
Arcas splendor (H.H. Druce, 1907) - Colombia and Ecuador
Arcas tuneta (Hewitson, 1865) - The Guianas to southern Brazil