Sciaroidea

As nematoceran flies, sciaroid adults generally have long segmented antennae, while their larvae have a well-developed head and mouthparts.^[1]

Aside from this, sciaroids vary in appearance. For example, Sciaridae adults have each eye extended dorsally to form an "eye bridge", a feature not found in related families.^[2] Cecidomyiidae adults have a distinctive reduced wing venation, while their larvae are atypical for nematoceran larvae in having a very small head capsule.^[3]

Most fungus gnats (Sciaroidea excluding Cecidomyiidae) live in forests with their larvae occurring in fungi, dead wood and soil. There are some which live in wetlands such as fens.^[4] Several genera of Sciaridae and Mycetophilidae may reach high abundances in damp buildings with wet organic matter.^[5]

Some species of Sciaridae and Cecidomyiidae are among the rare Diptera that spend their entire lives in soil. These are wingless as adults.^[6]

Sciaroid larvae typically feed on fungi but there are some which form plant galls (many Cecidomyiidae) or prey on other invertebrates (Keroplatidae).^[7]

A 2016 molecular phylogenetic analysis confirmed that Sciaroidea is a monophyletic group and should include both Cecidomyiidae and Ditomyiidae.^[8]

These 15 families belong to the superfamily Sciaroidea:^[9]

• Bolitophilidae Meigen, 1818
• Cecidomyiidae Newman, 1835 – gall midges and wood midges, sometimes excluded from Sciaroidea
• Diadocidiidae Winnertz, 1863
• Ditomyiidae Kylin, 1919
• Keroplatidae Rondani (incl. Lygistorrhinidae Edwards, 1925) – long-beaked & predatory fungus gnats
• Mycetophilidae Newman, 1834
• Rangomaramidae Jaschhof and Didham, 2002 – long-winged fungus gnats^[10]
• Sciaridae Billberg, 1820 – dark-winged fungus gnats
• † Antefungivoridae Rohdendorf, 1938
• † Archizelmiridae Rohdendorf, 1962
• † Eoditomyiidae
• † Mesosciophilidae
• † Paraxymyiidae Rohdendorf, 1946
• † Pleciofungivoridae Rohdendorf, 1946
• † Protopleciidae Rohdendorf, 1946