Erynnis pacuvius, also known as Pacuvius duskywing, Dyar's duskywing or buckthorn dusky wing, is a species of skipper butterfly in the family Hesperiidae. It is found in southern British Columbia and in most of the western United States.[1]
The wingspan is 29–33 mm. The flight period is between June and July in the north with a second generation in the south.[1]
The larvae feed on Ceanothus species.[2]