Abstract: Myrmica nefaria sp.n., a new social parasite, is described from Indian Himalaya with notes on its ecology. Workers, gynes and males of this species, as well as workers of the host species have been collected. The species differs well from all already described socially parasitic species of Myrmica, and is the second socially parasitic species recorded from Himalaya. This new species seems to follow Emery's rule in the strict sense, as it somewhat resembles morphologically its host, Myrmica rupestris Forel, 1902, and might have evolved from its host. Based on some other features it appears that this parasitic species is younger than its host. This discovery is bound to contribute a lot in the field of evolutionary biology in terms of speciation and origin of social parasitism.