Notes on the Plebejus christophi (Staudinger, 1874) (Lepidoptera: Lycaenidae) species group of China, with a description of a new species from the Eastern Tian Shan

A new species of the Plebejus christophi (Staudinger, 1874) species group, P. fantomas sp.n., is described from China, Xinjiang Uygur Autonomous Region, Karlik Mountains.The new species differs from other members of the P. christophi species group in peculiar blueish colouration of the ventral side of the wings and the characters of the male genitalia.The status of the taxon originally described as Lycaena christophi nanshanica Forster, 1936 is clarifi ed.It is considered as a distinct species distributed in the Qilianshan and the Altyn-Tagh mountains, P. nanshanicus (Forster, 1936), comb.et stat.n., based on the combination of the external characters and the characters of the male genitalia.The redescription of the species is provided along with a key to closely related species of the P. christophi species group of Mongolia and northwestern China discussed in this paper.