Mesopolobus amaenus (Walker, 1834) (Fig. 4)

Amblymerus amaenus Walker, 1834a: 307 . Lectotype ♀, BMNH (Examined, TYPE HYM 5.1847).

Mesopolobus amaenus (Walker): Rosen, 1958: 225; Graham, 1969: 676–677; Bouček, 1974: 247–276.

Synonym: Amblymerus nanus Walker, 1834b: 349; Eutelus dilectus Walker, 1834: 356–357; Eutelus immaculatus Walker, 1834b: 357; Eutelus eximius Walker, 1834: 360; Eutelus catenatus Walker, 1834b: 362–363; Eupelmus cecidomyinus Rondani, 1877: 177; Eupelmus circinantis Rondani, 1877: 178; Eutelus collaris Thomson, 1878: 74 .

Material examined. England. 1♀, SR. Arbrook Common. ex. galls of Biorniza pallida Oliv. 20–22 June 1952 , em. 6–9 July 1952, coll. J.F.Perkins; 1♂, SR. Oxshott Heath. 20–22 June 1952 , em. 28–30 July 1952, coll. D.M.S. Perkins. China. 1♀, Inner Mongolia, Hailaer, 3 August 1981, coll. Dingxi Liao ; 1♀, Hebei, Xinglong, 2 110 m, 24 June 1985, coll. Huafu Mi ; 1♀, Ningxia, Yinchuan, 25 July 1984, coll. Dingxi Liao ; 1♀, Xinjiang, Tashikuer, 8 July 1965, coll. Dingxi Liao ; 1♂, Xinjiang, Wulumuqi, 3 June 1965, coll. Dingxi Liao.

Biology. The species was reared from gall wasps (Askew, 1961). The hosts include Andricus corruptrix (Shirley, 1998a, 1998b), A. quercuscalicis (Hails et al., 1990), A. amenti, A. curvator, A. grossulariae, A. inflator, A. solitarius, Biorhiza pallida, Dryocosmus kuriphilus, Neuroterus saltans, N. quercusbaccaru, Synergus umbraculus, Trigonaspis synaspis (Herting, 1977), Cynips quercusfolii (Thompson, 1958) . There is no host record in our specimens.

Distribution. China (Inner Mongolia, Hebei, Ningxia, Xinjiang); Palearctic and Nearctic Regions (Noyes, 2014).