The Conopidae, usually known as the thick-headed flies, are a family of flies within the Brachycera suborder of Diptera. Flies of the family Conopidae are distributed worldwide in all the ecozones except for the poles and many of the Pacific islands. About 800 species in 47 genera are described worldwide, about 70 of which are found in North America. The majority of conopids are black and yellow, or black and white, and often strikingly resemble wasps, bees, or flies of the family Syrphidae, themselves notable bee mimics. A conopid is most frequently found at flowers, feeding on nectar with its proboscis, which is often long.