Propertius Duskywing

''Erynnis propertius'', the Propertius duskywing, is a butterfly of the family Hesperiidae. It is found in along the west coast of North America from southern British Columbia south along the Pacific Slope to Baja California Norte.

The wingspan is 35–45 mm. There is one generation with adults on wing from March to July.

The larvae feed on ''Quercus'' species, including ''Quercus agrifolia'' and ''Quercus garryana'' species. Adults feed on flower nectar.