Abstract
Previously only ten species of Hercostomus Loew were known to occur in Tibet, of which only two belong to the H. baishanzuensis group. Here the following six species of the H. baishanzuensis group are described as new to science: Hercostomus bisetus sp. nov., H. deltodontus sp. nov., H. flavus sp. nov., H. galonglaensis sp. nov., H. nuciformis sp. nov. and H. pailongensis sp. nov. A key to the species of the H. baishanzuensis group from Tibet is provided.