Realizing this looked like Enoclerus, I browsed Jacques Rifkin's Enoclerus images, and came across the similar looking (but not quite right) E. bimaculatus from AZ. A search on that species led me to the 4th image pair down on Margarethe's page here, which brought E. luscus to primary candidate status. Then I discovered Joyce's post below from the same night and locale.



So I guess this must be E. luscus...though it looks to me like this is a different individual than the one in Joyce's image (from the configuration of "hairless spots" on the distal sutural edge of the elytra).

Compare with Jacques Rifkin's image of E. luscus.