Description: They are about 1/2-inch long, black with an reddish-orange area on the top of the thorax, and a pair of smoky colored wings.
There are many other species of Bibionidae, called March flies. Other Texas species are generally black with clear wings and become abundant in certain periods of the year. They are all weak fliers. Larvae are not usually encountered.

Life Cycle: Large numbers of adults emerge primarily in the spring (May) and fall (September). Males and females fly and couple in open areas along roadways, appearing to swarm in weak flight. Although females live for only a week or so, adult flight activity lasts for a period of about 4 weeks. Eggs are deposited in swampy areas and ditches. Larvae develop through several stages (instars), becoming about 3/8 inch long and slate-gray with dark heads. Thereafter, they pupate in the soil and emerge as adults in about 8 days.

Habitat and Food Source(s): Larvae have chewing mouthparts. Adults fly mainly during daylight hours and feed on nectar and other moisture sources. They are naturally attracted to open areas such as roadways through wooded areas. Larvae feed on decomposing organic matter and sometimes plant roots.

Pest Status: High numbers in flight over roadways can be annoying, causing bug-splattered windows and radiator grills that can lead to obscured vision and engine overheating; medically harmless.

For additional information, contact your local Texas Cooperative Extension agent or search for other state Extension offices.

Literature: Drees 1990.