This small family of nematocerous flies is comprised of eight species in three genera. Of these, five extant species in the single genus Perissomma Colless) occur only in Chile and southeastern Australia. Very little is known of the immature biology. Published records indicate that larvae have been found in Boletus fungi and moist leaf litter.
Fossil representatives of this family are known only from Siberia and Mongolia in the Northern Hemisphere. Three fossil species in 2 extinct genera have been described.
GURVANIELLA Kovalev, 1986: 127. Type species: Gurvaniella hosbayari
Kovalev, 1986, by original designation.
hosbayari Kovalev, 1986: 128. PA: Mongolia (Upper Jurassic/Lower Cretaceous) [C].
PALAEOPERISSOMMA Kovalev in Kalugina & Kovalev, 1985:
115. Type species: Palaeoperissomma collessi Kovalev, 1985, by original
collessi Kovalev in Kalugina & Kovalev, 1985: 115. PA: Russia (Siberia) (Middle Jurassic) [C].
demetrii Kovalev, 1990: 133. PA: Russia (Siberia) (Upper Jurassic) [C].