The large blue (Phengaris arion, also known as Maculinea arion and Glaucopsyche arion) is species of butterfly in the Lycaenidae family. The species was first defined in 1758 and first discovered in Britain in 1795. In 1979 the species became extinct in Britain but has been successfully reintroduced with new conservation methods. Currently large blue is classified as "Near Threatened" on the IUCN red list of threatened species. Today P. arion can be found in Europe, the Caucasus, Armenia, West Siberia, Altai, North-West Kazakhstan and Sichuan.