Contributions to the knowledge of the myrmecophilous pselaphines (Coleoptera, Staphylinidae, Pselaphinae) from China. III. Two new genera and two new species of the subtribe Batrisina (Staphylinidae, Pselaphinae, Batrisitae) from a colony of Lasius niger (Hymeptera, Formicidae, Formicinae) in East China.