The Carnidae are quite small (1-2 mm) black flies and probably due to their small size, they have not attracted a great degree of study. One notable exception is Carnus hemapterus Nitzsch, which is parasitic on birds, and was therefore the centre of several studies. Most species of the Carnidae are saprophagous and are associated with carrion, faeces, or bird's nests. Worldwide there are five genera with 88 extant and two fossil species.
Information on morphology, biology, classification, and distribution of the Carnidae, together with a key to genera can be found in Hennig (1937), Sabrosky (1987), and Papp (1998), with some information also present in Brake (2000). The Nearctic species of the genus Meoneura were revised by Sabrosky (1959), and the genus Carnus was revised by Grimaldi (1997).
The phylogeny of the Carnidae was discussed by Hennig (1972), Grimaldi (1997), and Buck (2006). Meoneura and Carnus are sistergroups with the latter probably arising from within Meoneura. Sistergroup to Meoneura+Carnus is Hemeromyia, and sistergroup to these three genera is a clade consisting of Neomeoneurites and the fossil genus Meoneurites.
The position of the family within the Schizophora was discussed by Griffiths (1972), J. K. McAlpine (1989) and Buck (2006). Accordings to Buck's phylogenetic analysis Carnidae belong to the superfamily Carnoidea. The only genus of the Australimyzidae, Australimyza Harrison, has previously been included in the Carnidae by Colless & D. K. McAlpine (1991) and Grimaldi (1997). However according to Buck (2006) Australimyzidae are the sister group to Inbiomyiidae and are therefore not included in Carnidae. A revision of the genera Meoneura Rondani and Hemeromyia Coquillett is badly needed as well as a phylogenetic study of the family.