bee fly

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various flies of the family Bombyliidae that resemble bees, feed on nectar and pollen, and have larvae that are parasitic on the eggs and larvae of bees, wasps, and other insects.

from The Century Dictionary.

• noun Any dipterous insect of the family Bombyliidæ: so called on account of its resemblance to a bee.
• noun A dipterous insect, Phora incrassata, which is a formidable pest of the beehive, formerly considered capable of producing the disease called foul-brood. See Phoridœ.

from the GNU version of the Collaborative International Dictionary of English.

• noun any dipterous insect of the family Bombyliidae, which eat nectar and in some cases resemble bees. Their larvae are parasitic on the larvae of bees and other insects.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun hairy nectar-eating fly that resembles a bee; larvae are parasitic on larvae of bees and related insects