Ephyriades arcas, the Caribbean duskywing, is a butterfly of the family Hesperiidae.

It is found in Central America and the Caribbean, the type specimen being described from Saint Kitts.

[1] Upper side: Thorax and abdomen black.

Wings very dark brownish black, immaculate.

Under side: Legs, breast, and abdomen dark brown, but rather lighter than on the upper side, immaculate, except a small white spot on the anterior, placed near the anterior edge towards the tip.