O. Merkl szerk.: Folia Entomologica Hungarica 68. (Budapest, 2007)

the Hortobágy Diptera. Contrarily, adults of two species new to Hungary, Sepsis barbata BECKER, 1907 and Sepsisfissa BECKER, 1903 (PAPP 2004) were captured in 2003. The other species of Sepsis had been known from the pasture dung of the large hoofers in Hungary (including cow pats). Checking our list against the Diptera chapters of the book of the animals in the Hortobágy National Park (MAHUNKA 1983), we found ten other species, which have not formerly been collected in the Hortobágy NP. These are the following: Hybotidae: Crossopalpus minimus (MEIGEN, 1838); Phoridae: Diplonevrafunebris (MEIGEN, 1830), Metopinapileata SCHMITZ, 1936; Sphaeroceridae: Elachisoma bajzae L. PAPP, 1983, Elachisoma kerteszi (DUDA, 1924), Trachyopella melania (HALIDAY, 1836), Philocoprella italica (DEEMING, 1964), Rachispoda pseudohostica (DUDA, 1924); Milichiidae: Leptometopa latipes (MEIGEN, 1830);Sarcophagidae: Taxigramma heteroneurum (MEIGEN, 1830). Species pool As regards species richness of the dung inhabiting flies on the pastures of Hungary, PAPP (1992) listed 270 to 280 species of 26 Diptera families. For quantitative ecological studies (such as species richness estimations, species abundance distributions, etc.) that number is proposed to regard as the potential species pool (cf. IZSÁK & PAPP 2008). The species composition of those 106 species is dominated by widespread Palaearctic species characteristic for the plains and hilly parts of Hungary. If our basic multitude is regarded to belong to a single guild of flies in a first approach, that would mean that all they are actually characteristic species of cow pats. After having made some considerations, wc left in the basic tables of data not only the true dung feeders and special predators living in the cow pats, but also all those flies, which live not upon dung, but which are present regularly on the surface of cow pats, see above. However, there are only a rather few species among the flics sampled, whose larvae are not dependent on dung as medium of development. Their presence is not by chance, though. Ochlerotatus dorsalis (MEIGEN, 1830) (Culicidae) and the chloropid species are on the dung, because they find it as a microsite of higher humidity. The species Medetera micacea LOEW, 1857 (Dolichopididae) hunts probably on small flies over the surface of the cow pats. A tachinid species, Dinera grisescens (FALLÉN, 1817) is a parasitoid of carabids living under the crust of older cow pats. Consequently, it is not a surprise to find always the same tachinid species, though