Satyrium saepium caliginosum

Dark Hedgerow Hairstreak

This subspecies is best known from the cool San Luis Obispo coastal chapparal habitats where the host Ceanothus cuneatus is present. It differs from subspecies chalcis by the "two-toned" look of the ventral side of the wings; the basal two-thirds is relatively dark. They fly in a single brood from the middle of June through July, peaking around the first of July.

So there are currently four subspecies of saepium in southern California: chalcis covers nearly all of the southern California populations (TL: Isabel Creek, Santa Clara Co.); caliginosum is in a limited area along the immediate coast of SLO and perhaps SB counties (TL: Baywood Park in SLO); chlorophora is in coastal San Diego county (TL: San Diego); and subaridum from the high desert east of the Sierras (type locality: Hunter Mountain in Death Valley NP). The saepium of Santa Cruz Island are said to be very similar to caliginosum.

Photo of Satyrium saepium caliginosum
In the hills near Cal Poly S.L.O., there appears to be a bit of a blend zone with chalcis and a mix of phenotypes, but once out of the fog zone around Lopez Mountain the saepium are typical chalcis. This one is from Reservoir Canyon Loop Trail. June 14, 2021.
Photo of Satyrium saepium caliginosum
Another one from the same hike as above. The Ceanothus used here and in the classic spots closer to the coastline is the same. June 14, 2021.

©Dennis Walker