Abstract
Ilybius thynias sp. n. is a new member of the Ilybius chalconatus-group and belongs to the subgroup of the same name. It was collected in the European part of Turkey, not far from the westem coast of the Black Sea, some kilometres west of Igneada andsomewhat south of the border with Bulgaria. The species is extemally similar to the other members of that subgroup, but males deviate considerably by the shape of the median lobe and the parameres. A detailed description and several figures are given tofacilitate an easy identification of the new species. In addition, we have modified the key to species for males of the chalconatus- and erichsoni-groups given in Fery & Nilsson (1993) by including the new species and the similar, only recently described, I. adygheanus Petrov, Shapovalov & Fery, 2010. The genus Ilybius Erichson, 1832 contains now 70 members, 21 of which belong to the chalconatus-group which includes the chalconatus-suhgroup with eight species. A synopsis of the chalconatus-group is presented.
NSTL