Maculinea arion (Linnaeus, 1758) - Large Blue.
As far as I know, this species included into an international Red Book, as well as other Maculinea species, as becoming scarce everywhere in Europe thanks to depletion of ants with which they are tightly connected as commensals. At least in Siberia and the Far East these species are still quite common.
Range: Europe (except for the North), South Siberia, Primorye, Mongolia, N China, Korea.
ssp.: ruehli (Krulikowsky, 1892) (= baschkiria (Krulikowsky, 1897)): range: Ural and West Siberia.
A copulating pair; wings closed.
A meadow in the Opalikha Rivulet valley just upstream of its fall into the Koen River, Iskitim District, Novosibirsk Province, West Siberia, Russia. 11th July 1992. O. Kosterin..