| abstract | A new feather mite Trouessartia cettiae sp. n. (Analgoidea: Trouessartiidae) is described from the Cetti’s Warbler Cettia cetti (Passeriformes: Cettiidae) from the south of European Russia. Being most close to T. carpi Till, 1954, the new species differs from the latter in the following: in both sexes, setae c3 and sRIII have a small subapical denticle; in males, the apophyses of adanal apodemes are situated posterior to the level of adanal suckers, and setae 4b are situated distinctly anterior to the level of setae 3a; in females, setae h1 are 5–8 μm long, the copulatory opening is distant from the free margin of interlobar membrane, and the posterior part of the hysteronotal shield is entirely covered with well-outlined circular and ovate lacunae. A brief note on a world distribution of the genus Trouessartia is provided. |