Syrphid flies are common, brightly colored flies. Typical markings are yellow or orange with black,and they may look very similar to bees or yellowjacket wasps. Syrphid flies are harmless to humans, however. The adults usually can be seen feeding on flowers.

It is the larval stage of a syrphid fly that is an insect predator. Variously colored, the tapered maggots crawl over foliage and can daily down dozens of aphids. Syrphid flies are particularly important in controlling aphid infestations early in the season and are capable of entering the tightly curled leaves some aphids produce. A tarry excrement produced by syrphid fly larvae is diagnostic of their activities.

A few species of syrphid flies, known as bulb flies, develop by feeding on and tunneling into plant tissues. Also common are drone flies (Eristalis spp.) excellent mimics of honey bees. In their larval form, known as rattailed magot because of the long breathing tube it possesses, drone flies develop in very moist soil or polluted water.

Return to Garden Insects of North America book description page