Abstract: Myrmica hirsuta Elmes, 1978 (Hymenoptera, Formicidae), a social parasitic myrmicine ant new for Carinthia. - Myrmica hirsuta, a social parasite in nests of Myrmica sabuleti Meinert, 1861, has recently been found in the Lieser Tal, Carinthia, Austria (13°36'00" / 46°56'01") in a dry meadow. This is the third report from Austria besides populations found in the Burgenland (Assing 1987) and Styria (Bregant 1988), and the first report for Carinthia. Densities of the host-ant as well as of the parasitic ant were estimated by nest-counting in two 3,3 m x 3,3 m squares in heterogen sites (dry area / more eutrophic area) of a 35 m x 120 m dry meadow (exposure Se, 40° inclination). Nest densities: in square A (upper dry zone) 5 nests of M. sabuleti, 2 nests infested by M. hirsuta; in square B (more eutrophic zone with a stone-wall on base): 3 nests of M. sabuleti, 1 nest infested by M. hirsuta. Myrmica hirsuta workers could not be registered. Comments on behaviour, distribution in Europe, and biology are given.