Can this possibly ALSO be B. flavifrons? I observed two very different-looking bees right after one another on adjacent plants. This one is electric yellow; the other has cream-colored face and shoulders (see https://www.inaturalist.org/observations/60246556).
But they have the same abdominal pattern, and I can't find another bee in the Williams/Thorp/Richardson/Colla field guide (or elsewhere) that can show the same combination.