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. Drusus krpachi sp. n. is a micro-endemic of the Korab Mountains, Macedonia, and D. malickyi sp. n. is a micro-endemic of the Prokletije Mountains, Albania. Both new species are most similar to D. macedonicus 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 Cryptothrix nebulicola McLachlan, Drusus chrysotus Rambur, D. discolor Rambur, D. macedonicus Schmid, D. meridionalis Kumanski, D. muelleri McLachlan, D. romanicus Murgoci and Botosaneanu, and D. siveci 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.