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Flies from June to August depending on location.
Wingspan: 17 to 28 mm.
Lycaeides argyrognomon lotis (syn. Lycaeides idas lotis, formerly Plebejus argyrognomon ) is a critically endangered butterfly endemic to Mendocino County, California, with sightings in Sonoma County and Marin County. It has been listed as an endangered species since June 1, 1976, but has not been sighted in the wild since 1994.