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Family Sciaridae - Dark-winged Fungus Gnats

Some kind of march fly? Unknown fly (?) Sciaridae gnat Unknown fly on milkweed Diptera another colorful bycatch - female Eugnoriste?
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Diptera (Flies)
No Taxon ("Nematocera" (Non-Brachycera))
Infraorder Bibionomorpha (Gnats, Gall Midges, and March Flies)
Superfamily Sciaroidea (Fungus Gnats and Gall Midges)
Family Sciaridae (Dark-winged Fungus Gnats)
Other Common Names
Mushroom Flies (Lycoriella)
Black fungus gnats
Synonyms and other taxonomic changes
Formerly treated a subfamily in Mycetophilidae
NA fauna revised in Mohrig et al. (2012)(1)
Explanation of Names
Sciaridae Billberg 1820
see Sciara
~170 spp. in 25 genera in our area(1), close to 2500 spp. in 92 genera total(2)
1-11 mm(3), usually under 5 mm
Small dark flies. Typical wing venation:

The larvae are white, slender, legless, with a black head and smooth semi-transparent skin revealing digestive tract contents.
Identification of adults at the species level is based primarily upon males which must be cleared with NaOH or KOH and mounted on slides. There is currently (2014) no way for a non-expert to identify most specimens even to genus.
worldwide(4) and throughout NA(3)
Mostly forests, swamps, and moist meadows (adults in foliage, larvae on fungi, decaying vegetation, plant roots, rotten wood, under bark, etc.); some live in extreme habitats (antarctic islands, mountains above 4,000 m, deserts); several spp. live exclusively in caves. Often found in flowerpots. In moist and shadowy areas up to 70% of all Diptera species can be Sciaridae.(4)
Life Cycle
1. Larva. 2 and 3. Pupae. 4 and 5. Wingless adult females. 6. Winged female. 7. Adult male.
Sometimes abundant enough to form a crawling mass of several inches across and several feet long, similar to armyworm migrations(3). Can be pests in greenhouses and in commercially grown mushrooms.(3)(4)
Internet References