Glaucopsyche piasus umbrosa, the 'Smoky' Arrowhead Blue, was flying off Old Highway 80 near Guatay in rural San Diego Country on May 11, 2013.
Another umbrosa above and below on the same day. The host is a Lupine - Lupinus formosus.
Special thanks to Andrew Kim for the location; I'd been on the lookout for these many times up at Laguna Meadow, the Typle Locality, and had never found them there.
©Dennis Walker