These beetles are commonly called jewel beetles, or metallic wood borers.
The family name is Buprestidae, so they may be called buprestids as well.
Aren't they colorful? Do you think they are trying to mimic wasps?
It turns out that some of these beetles even fly with their top wings (elytra) closed and only use their membranous underwings to fly. Most beetles, for example our common lady beetles, fly with their elytra up and opened. By flying with their elytra closed, the buprestid beetles look even more like wasps.
The buprestids in these photographs were feeding on flowers in Ramsey Canyon, in southeastern Arizona. These are probably in the Genus Acmaeodera, although it is very difficult to tell one from another.