Abstract
The cavities in trees (called dendrotelmata) in an urban environment stand at the periphery of researchers’ attention. This paper presents new data on the occurrence of three Diptera species considered as endangered, namely Systenus leucurus Loew, 1859, S. tener Loew, 1859 (both Dolichopodidae), and Lepiseodina rothschildi (Eaton, 1912) (Psychodidae) from just such a specific urban ecosystem in Prešov. The latter two species were also recorded for the first time in Slovakia. The distribution and conservation status of the reported species are reviewed and briefly discussed.