I found this single "different looking" individual among many photos I took of abundant Chauliognathus lewisi on flowers of the desert shrub Gutierrezia microcephala.

Unlike all the other Chauliognathus in my photos, this one keys to C. fasciatus in the 1964 treatment by Fender, and the description of C. fasciatus in Fender matches it very well. Moreoever, as with C. lewisi, Fender gives a locality record for C. fasciatus from Ivanpah, CA ... which is very near where the photos were taken. The type specimen images from MCZ look good too, especially if you cross-reference with the quote below from the species description in Fender(1) (italics are mine):

"pronotum yellow with a large urn-shaped median black spot, varying to yellow with a small round spot medially on each side"

The type specimen (from Utah) and the other two current BG posts from Utah (here and here), together with my image above, illustrate the range of variation of pronotal markings in C. fasciatus, as described by Fender.

I wish I would have noticed the presence of this 2nd species while in the field, as I would have looked more closely for other C. fasciatus among the many swarms of Chauliognathus seen at various sites in the general area, during that day and the next.

Interestingly, I photographed this same individual a few seconds later, as it appeared to try to dislodge and replace the male of a mating pair of C. lewisi...see the 2nd image of this series. So I think this is a male, which may be discernible to cognoscenti from the terminalia visible in this image. Note also the visibly swollen 1st antennal segment, in reference to my remarks at the end of the post below: