Click on image to view larger. Syrphid flies or flower flies
This is a large group of flies, ranging from 1/4 to 3/4 inch long. Most adult syrphid flies are black or brown with yellow banded abdomens and body markings, superficially resembling bees and wasps. Some species are hairy and have a long, thin abdomen. Antennae are short (not elbowed). Larvae of most species are legless spindle-shaped instars and vary in color from creamy-white to green or brown.
Generally considered beneficial because the larval stages of many species are predaceous on insect pests such as aphids and adults pollinate flowers.
In general, females oviposit a single egg on leaves near aphid infestations or near other suitable food source for that species. Larvae hatch in about 3 days and develop through several instars over a period of 2 to 3 weeks before pupating, either on the host plant or in the soil. The skin of the last instar forms the tan-brown teardrop shaped puparium. Adults emerge in 1 to 2 weeks unless the pupal stage remains through the winter. Up to 7 generations occur annually.