Sciaridae Billberg, 1820

Minute to medium sized (0.8-8.0 mm), delicate, usually dark coloured Nematocera, with non-piercing mouthparts. Eyes with few exceptions connected in both sexes by a narrow eye-bridge; three ocelli present; antennae long and slender, with 16 segments. Wings mostly normal with anal lobe present, but wings may be reduced, and some forms are completely apterous; often darkened (hence the common name "black fungus gnats"); costa and R-veins slightly stronger than other veins; two highly characteristic forks are formed firstly by M-stem, M1 and M2 and secondly by CuA1, CuA2 and the generally short CuA-stem. Legs long and slender. The larvae are mostly free living in the upper soil layer of nearly all terrestrial habitats; some species develop inside plant stems, leaves or decaying wood. They feed on fungal mycelia or decomposing plant tissue. The adult flies fulfill mainly a reproductive function and at most take up liquids, as the mouth parts are often reduced.

Altogether 630 valid species are listed in the Fauna Europaea (Heller & Menzel 2007), but menawhile more than 700 are published. 262 species are listed in the present checklist: 230 in the Czech Republic (169 in Bohemia, 163 in Moravia), and 135 in Slovakia). Since the ECV1 (Heller & Menzel 2006), the number of species in the Czech Republic has increased by one species (one addition and one deletion in Bohemia and no changes in Moravia), the biggest increase was in Slovakia with 83 species (84 additions, one deletion). No species names have been removed from the previous version, but some taxonomic changes were necessary due to synonymy in one case and some minor errors in the previous list. From penultimate version of the checklist (Rudzinski & Košel 1997) 18 species names had been removed, because four names are considered synonyms, for 13 there was found no published reference [Bradysia inusitata Tuomikoski, 1960; Bradysia longistylia Mohrig & Krivosheina, 1982; Bradysia pauperata (Winnertz, 1867); Bradysia rufescens (Zetterstedt, 1852); Bradysia submoesta Mohrig & Krivosheina, 1989; Chaetosciara estlandica (Lengersdorf, 1929); Corynoptera montana (Winnertz, 1869); Cratyna schineri (Winnertz, 1867); Corynoptera nigrohalteralis (Frey, 1948) = Dichopygina nigrohalteralis (Frey, 1948); Phytosciara prosciaroides (Tuomikoski, 1960); Sciara lackschewitzi (Lengersdorf, 1934); Trichosia coarctata (Winnertz, 1867); Xylosciara betulae Tuomikoski, 1960] and one species, Bradysia soudeki Kratochvíl, 1936, is considered a nomen dubium. The species richness of the sciarid fauna is comparatively well known in the Czech Republic and now also in Slovakia, but in each country over 400 species should be expected.

An extensive revision of the whole family was given in Menzel and Mohrig (2000), which also contains a key to the genera and species groups. All species can be reliably distinguished by the structure of the male terminalia, but currently no key covering all the species of Central Europe is available because the number of newly discovered and described species is constantly increasing. The nomenclature used in the Fauna Europaea (Heller & Menzel 2007) and by Menzel and Mohrig (2000) is adopted as the basis for the present checklist, but for the recently established genera Cosmosciara, Claustropyga and Dichopygina we follow Menzel and Heller (2007), Hippa et al. (2003) and Vilkamaa et al. (2004), and we also include the new status of some further individual species revised by Menzel and Heller (2005, 2006, 2007) and Heller et al. (2009).