This is Strymon avalona, the Avalon Scrub Hairstreak, which is found only on Santa Catalina Island. May 19, 2013.
Another Strymon avalona from the same trip. These were found along a dirt road above Two Harbors, which is on the northeast part of the Island. Santa Catalina Island is about 26 miles from the shore in Long Beach.
The dorsal of Strymon avalona, showing what must be structural coloration.