Syrphid flies
Syrpus species

Description: These insects commonly are referred to as "sweat flies." Adults of this very large group also are called flower flies, hover flies and sweat flies. Many are brightly colored and resemble bees or wasps. They feed on nectar and pollen and pollinate many plants. Many hover motionless in the air except for the beating of their wings; others fly with a buzzing sound like that of bees. Adults lay glis-tening, white, elongated eggs among groups of aphids. Syrphid fly larvae, as a group, vary consid-erably in habits and appearance. Length varies from 1 /4 to 1 /2 inch when fully grown. Larvae are varying shades of yellow, pink, green or brown marked with black or white. Their bodies are point-ed at the head end, broad at the tail end, and somewhat depressed. They are elongated, legless and slug-like.

Prey: Larvae commonly are found among aphid colonies. They move slowly over the surface of the plant, grab aphid after aphid with their pointed jaws, raise them into the air, and slowly suck out the body contents. Then they discard the empty skin. Larvae often destroy aphids at the rate of one per minute over a considerable period of time.