Bee Fly

Identifying Features: Hovering fly with densely hairy body and long, beak-like mouthpart, front parts of wing black.
This fly is found in July and August on bright sunny days as it hovers around flowers. They readily are seen in gardens and hover and nectar like miniature hummingbirds. The females lay their eggs in the burrows of ground nesting solitary bees and the fly larvae parasitize the bee larvae, usually after the bee larvae pupates.
The wings of these flies are almost constantly in motion as they nectar, perhaps in order to escape predators such as crab spiders. In an instant they can zip away out of danger. They have large compound eyes and also have the ability to sense air motion, all of which makes them difficult to approach.
http://share3.esd105.wednet.edu/rsandelin/Fieldguide/Animalpages/Insect…