Description of two new filtering carnivore Drusus species (Limnephilidae, Drusinae) from the Western Balkans.

Two new species of the genus Drusus (Trichoptera, Limnephilidae, Drusinae) from the Western Balkans are described. Additionally, observations on the biodiversity and threats to the region's endemic aquatic fauna are discussed. Drususkrpachi sp. n. is a micro-endemic of the Korab Mountains, Macedonia, and Drususmalickyi sp. n. is a micro-endemic of the Prokletije Mountains, Albania. Both new species are most similar to Drususmacedonicus but differ from the latter in the shape of segment IX, the shape of the tips of the intermediate appendages in lateral view, the shape of the inferior appendages, and the form and shape of the parameres. In addition, males of the European species of filtering carnivore Drusinae are diagnosed and illustrated, including Cryptothrixnebulicola McLachlan, Drususchrysotus Rambur, Drususdiscolor Rambur, Drususmacedonicus Schmid, Drususmeridionalis Kumanski, Drususmuelleri McLachlan, Drususromanicus Murgoci and Botosaneanu, and Drusussiveci Malicky. These additions to the Western Balkan fauna demonstrate the significance of this region for European biodiversity and further highlight the importance of faunistic studies in Europe.