In our study, using the analysis of DNA barcodes and morphology (wing color, male genitalia, and female sphragis shape), we show that the group of species close to comprises the western and eastern phylogenetic lineages. The eastern lineage includes , and . The western lineage includes three morphologically similar species: (Western Eurasia), (southwestern Europe), and . (Turkmenistan and NE Iran), as well as the morphologically differentiated (Altai). The latter species differs from the rest of the group in the presence of red spots on the wings. s.s. is represented by four differentiated mitochondrial clusters that show clear association with specific geographic regions. We propose to interpret them as subspecies: (Central and Eastern Europe, N Caucasus, N Turkey), (the Middle East), (Tian Shan), and (Gissar-Alai in Central Asia). We demonstrate that in the red spots on the wing evolved as a reversion to the ancestral wing pattern. This reversion is observed in Altai, where the distribution areas of the western lineage, represented by , and the eastern lineage, represented by , overlap. These two species hybridize in Altai, and we hypothesize that the color change in is the result of reinforcement of prezygotic isolation in the contact zone. The lectotype of var. Christoph, 1873, is designated.
