Comptosia. The biology of this group is not well documented. The larvae may feed on ants, beetles or other insects.

Adults are usually seen feeding on nectar at flowers or touching down on sand. Larva typically attack ground-nesting wasps & bees - as ectoparasites, kleptoparasites or predators.
Anthrax maculatus

These banded bee flies are common and have been abundant all summer. They vary in size, and some are tiny.
Villa, or another member of the tribe Villini