I think this should now be Pelochrista eburata (Heinrich, 1929)? From BG page "Pelochrista williamsi (Powell, 1963) is a synonym of 3085 Pelochrista eburata (Heinrich, 1929), MONA Fascicle 9.5: 89.".

Matched with several nice San Diego County examples from Mark Dreiling on BG https://bugguide.net/node/view/796640