Redescription of three species of Oligonychus (Acari, Tetranychidae) from China

Two species of Oligonychus are redescribed: O. baipisongis Ma & Yuan, 1976 and O. chamaecyparisae Ma & Yuan, 1976. Moreover, O. hainanensis Ma, Yuan & Lin, 1979 is here recognized as a junior synonym of O. biharensis (Hirst, 1924), which is also redescribed here based on adult females, males and deutonymphs. The redescription of O. baipisongis is based on holotype and paratypes, the types of O. chamaecyparisae could not be located but the species is described from male and female material collected by En-Pei Ma in 1978 from Lanzhou City, Xi-An City and Xining City. The dorsal setae in O. baipisongis show remarkable sexual dimorphism. The difference between the aedeagi of O. chamaecyparisae and Oligonychus perditus Pritchard & Baker, 1955 are discussed. All three species are diagnosed, illustrated with line drawings and photographs.