3. Trechus cardioderus balcanicus Jeannel, 1927 (stat. res.), revived from synonymy with T. irenis

The name Trechus cardioderus balcanicus is not supposed to be in use anymore since the established by Moravec & Lompe (2003) homonymy of T. cardioderus balcanicus with T. (Anophthalmus) balcanicus Frivaldszky, 1879 = Duvalius (Paraduvalius) balcanicus (Frivaldszky, 1879) . In accordance with the International Code of Zoological Nomenclature Art. 23.9.5. (ICZN 1999), as the taxa T. cardioderus balcanicus and D. balcanicus were not considered congeneric after 1899, we must not automatically replace the junior homonym, and the case should be referred to the International Commission on Zoological Nomenclature. Until its decision, the prevailing usage of the name will remain.

Type material: Type: Bosnia and Herzegovina: 1♂, Žepče, Apfelbeck, 1903 (coll. Jeannel, MNHN); Paratypes: Bosnia and Herzegovina: 1♂, Srnetica planina, V. Apfelbeck (coll. Jeannel, MNHN) ; 1♂, Kamenica, Apfelbeck (coll. Jeannel, MNHN) ; 1♂ H. Koprivnica, près de Kupres, Apfelbeck (coll. Jeannel, MNHN) ; Serbia: 1♂, Stopica pecina, à Rojantsvo (coll. Jeannel, MNHN) .

Other material examined: Bulgaria: Stara planina Mts.: 1♂, Kotel, “Lednitsata” Cave, “Zlosten” Place, 11.03.2011, B. Petrov leg. (NMNHS); 2♂, Berkovitsa–Kom, 07.08.2016, R. Bekchiev leg. (BFUS); 1 ♂, Medven Vill., the river, N42.85172 E26.55142, 08.08.2019, R. Kostova leg. (BFUS); Ruy Mt.: 2♂, 1♀, 2 km N from Lomnitsa Vill., “Transko zhdrelo” Place, 9– 10.07.2007, B. Guéorguiev leg. (NMNHS)

Notes: Relatively small: the body length of males is 3.95–4.76 mm. The body’s dorsal surface is brown or dark brown and unicolourous. Reduced wings. Median lobe of the aedeagus: the apex in the lateral view is strongly elongated and curved downwards; the elongation is also visible dorsally, with the apical lamella separated from the main part of the median lobe by constriction, occasionally rather deep (Fig. 3). The studied material from Bulgaria fully corresponds to the description and male genitalia drawing of Jeannel (1927: 455) and to the drawing of Nonveiller et al. (1994: 14), as well as to the material of the T. cardioderus balcanicus type series in the collection of R. Jeannel at MNHN.