Karyotype of 3 species of the genus Orius Wolff were firstly studied using the Giemsa staining and squashing slides method in male germ cell. It is reported that number of chromosome and system of sex chromosome of haploid chromosome complement of these species is n=11A＋X （Y） in the first meiotic stage. However, the behavior of chromosomes among the species are different distinctly, thus cytotaxonomic character can be adopted to the identification among the three species.
Immature stages of 3 species of the tribe Ozophorini from China are described for the first time, they are Bryanellocoris orientalis Hidaka (3rd^5th instars), Primierus longispinus Zheng (4th^5th instars) and Vertomannus brevicollum Zheng (4th^5th instars). Abrief study on fine structure of pale spots on head, pronotum and abdomen of 5th instar nymph of Bryanellocoris orientalis Hidaka was also given.
