In this paper a new species of the genus Endasys Foerster parasitizing reddish larch sawfly (Pachynematus itoi Okutani) is described. The type specimens are deposited in the General Station of Forest Pest Management, Chinese Ministry of Forestry. Endasys liaoningensis, sp. nov. (Figs. 1 apprx 4) This new species is similar to E. lygaeonematus (Uchida), but can be distinguished from the latter by the following characters. Upper tooth of mandible a little longer than lower tooth; basal 4 flagellar segments black, 5-9 whiter, propodeal spiracle oval, areola 2. 3 times as wide as long. Holotype; female Liaoning: Xinbin, 20 - VI - 1992. paratypes: 36 female female , 30 male male , 10 apprx 30 - VI - 1992. Host: Pachynematus itoi Okutani.