Robber flies are predatory insects that catch their prey, which are other insects, while flying. Their eyesight is amazing. They have been compared to falcons of the bird world.
The one we see in the Skiatook area is present from June through Fall. It has a “bearded” (bristled) face (see photos). After catching an insect, they use their short, strong proboscis to suck out the prey’s body fluids. Beekeepers call them “bee killers” because of their preference for honeybees.