Bibionidae are medium-sized flies with a body length from 4.0 to 10.0 mm. The body is black, brown, or rusty, and thickset, with thick legs. The antennae are moniliform. The front tibiae bear large strong spurs or a circlet of spines. The tarsi are five-segmented and bear tarsal claws, pulvilli, and a well developed empodium. The wings have two basal cells (posterior basal wing cell and basal wing cell), but are without a discoidal wing cell. R4+5 is simple or branched; at most, only three branches of R developed. The leading edge wing veins are stronger than the weak veins of the trailing edge.
Bibionid larvae grow up in grassy areas and are herbivores and scavengers feeding on dead vegetation or living plant roots. Some species are found in compost. Larvae are sometimes found in pockets in which sometimes up to 200 specimens have been counted. Adults of most Plecia and some species of Bibio do not eat, but subsist solely on the food taken in during the larval stage and drop steadily when in flight until they are a few inches above the ground, hovering slowly. Adult-stage bibionids are quite short-lived, and some species of Plecia (lovebugs) spend much of their adult lives copulating. The male and female (lovebugs) attach themselves at the rear of the abdomen and remain that way at all times, even in flight. Adults swarm after synchronous emergence, sometimes in enormous numbers.
Bibionids have the most extensive fossil record of any dipteran family. Fossil bibionids are known questionably from the Jurassic, while some forms from the early part of the Upper Cretaceous look quite similar to modern species. Bibionid flies are very abundant among insect fossils from the Tertiary period, and a large number of species have been described, although often based on highly fragmentary material. Most fossil species are easily identified with extant genera. In particular, the genera Plecia and Bibio are abundant among Tertiary fossils. Fossils from Europe include a large number of specimens of the mainly tropical genus Plecia which is today entirely absent from Europe, demonstrating a warmer climate during the Tertiary.
Adults feed on the nectar of flowers of fruit trees and especially on flowers of umbelliferous plants; often swarming in mass flights in spring. Adults are important pollinators. Larvae play an important role in formation and accumulation of humus in soil. Some larvae are serious plant pests, especially of pasture land and other agronomic crops including cereal crops, vegetables, forage crops, and seedlings of many other plants.
The Nematoceran family Axymyiidae is the sole member of the infraorder Axymyiomorpha, though it is often included within the infraorder Bibionomorpha in older classifications. It is known from only seven species in three genera, plus three fossil species.Bibio (fly)
Bibio, march flies or St. Mark's flies, is a genus of flies (Diptera).Bibio abbreviatus
Bibio abbreviatus is a species of March flies in the family Bibionidae.Bibio anglicus
Bibio anglicus is a species of flies from the family Bibionidae.Bibio lanigerus
Bibio lanigerus is a species of flies in the family Bibionidae. It is found in the Palearctic.Bibio longipes
Bibio longipes is a species of flies in the family Bibionidae. It is found in the Palearctic and the Nearctic.Bibio marci
Bibio marci or St. Mark's fly or Hawthorn Fly is a species of fly from the family Bibionidae. It is found across much of Europe. Their common name comes from the fact that the adults usually emerge around St Mark's Day, 25 April.Bibio nigriventris
Bibio nigriventris is a species of flies in the family Bibionidae. It is found in the Palearctic.Bibio pomonae
Bibio pomonae, common name red-thighed St Mark's fly or heather fly, is a species of flies (Diptera) belonging to the family Bibionidae.Bibiodes
Bibiodes is a genus of March flies (Bibionidae).Bibionellus
Bibionellus is a genus of March flies (Bibionidae).Bibionomorpha
The Bibionomorpha are an infraorder of the suborder Nematocera. One of its constituent families, the Anisopodidae, is the presumed sister taxon to the entire suborder Brachycera. Several of the remaining families in the infraorder (those shown without common names) are former subfamilies of the Mycetophilidae, which has been recently subdivided. The family Axymyiidae has recently been removed from the Bibionomorpha to its own infraorder Axymyiomorpha.
Most representatives of the Bibionomorpha are saprophages or fungivores as larvae with the Cecidomyiidae being predominantly gall-formers. Some Sciarids are common indoor pests, developing large populations in potting soil that has become moldy from overwatering. The larvae of the Bibionidae sometimes migrate in large, snake-like masses to minimize dehydration while seeking a new feeding site.D. Elmo Hardy
Dilbert Elmo Hardy (September 3, 1914 – October 17, 2002) was an American entomologist who specialized in Diptera systematics.Dilophus
Dilophus is a genus of March flies in the family Bibionidae. There are at least 200 described species in Dilophus.Dilophus febrilis
Dilophus febrilis is a species of flies feverflies in the family Bibionidae. It is found in the Palearctic.Enicoscolus
Enicoscolus is a genus of March flies (Bibionidae).Lovebug
The lovebug (Plecia nearctica) is a species of march fly found in parts of Central America and the southeastern United States, especially along the Gulf Coast. It is also known as the honeymoon fly or double-headed bug. During and after mating, matured pairs remain together , even in flight, for up to several days.The species was first described in 1940 by D. E. Hardy, but was seen in Louisiana as early as 1911. At that time, he reported the incidence of lovebugs to be widespread, but most common in Texas, Florida, Alabama, Mississippi, and Louisiana. However, by the end of the 20th century the species had spread heavily to all areas bordering the Gulf of Mexico, as well as Georgia and South Carolina. L. A. Hetrick, writing in 1970, found the bug was also widespread in central and northern Florida and described its flights as reaching altitudes of 300 to 450 metres (980 to 1,480 ft) and extending several kilometers over the Gulf.Lovebugs' larvae feed on partially decayed vegetation in the landscape and, in this respect, are beneficial to humans. Adults primarily feed on nectar from various plants, particularly sweet clover, goldenrod, and Brazilian pepper.Penthetria
Penthetria is a genus of March flies (Bibionidae).Plecia
Plecia is a genus of March flies (Bibionidae).
Extant Diptera families