Bee flies are large, fat, and hairy, often with a long, rigid proboscis. They are excellent mimics of bees, and may have black and yellow stripes along the abdomen. The adults are avid seekers of nectar from various flowers, although a few species feed on pollen. They are important pollinators, and can reach the nectaries of many wildflowers that are inaccessible to other flies. Their larvae are brood parasites on various species of bees and wasps.