Based on the club-shaped antennae, as well as wing venation (for both see (1)
page 513), this should be another Pseudomasaris.
An earlier submission of another, larger species, prompted Eric Eaton to draw attention to the unique antennal shape. (See 1
Seen here nectaring on Asclepias vestita. If this species is also associated with Penstemon, they are just beginning to bloom. I'll check up on that in the next couple of weeks.
Species ID by Doug Yanega (Dept. of Entomology, Entomology Research Museum, UC Riverside, CA)