Maculinea nausithous (Bergstrasser, 1779) (= Maculinea arcas Rottemburg, 1775) - Dusky Large Bue.
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: the southern forest and forest-steppe zones from W Europe to Central Siberia.
ssp.: nausithous (Bergstrasser, 1779) - ?monotypical.
A female on the larval foodplant Sanguisorba officinalis L.
A forest-steppe landscape in the vicinity of Akademgorodok [Academy Town], Novosibirsk, West Siberia, Russia. 7th August 1988. O. Kosterin.