Family Bombyliidae (Bee Flies): A pollinator with a bad reputation. They are among the many flies that imitate bees, bumble bees specifically. By hovering, instead of landing, they avoid many predators hiding in the flowers.
Adults generally feed on nectar and pollen, some being important pollinators. Larvae generally are parasitoids of other insects, including bees. The adult females usually deposit eggs in the vicinity of possible hosts, quite often in the burrows of beetles or wasps/solitary bees.
Bee flies also facilitate pollination of many species of flowering plants. While they do not land on the flower, they do carry some pollen from plant to plant. It is thought they are just as efficient pollinators of some types of flowers as are the bees and they are more frequent visitors so, in the end, they may a pollinate more flowers than bees.