Three new species of fossil Palaeontinidae are described from Daohugou Village, Inner Mongolia, China: Daohugoucossus shii sp. nov., D. parallelivenius sp. nov., D. lii sp. nov. The diagnosis of Daohugoucossus Wang, Zhang and Fang, 2006 is revised. These materials are the first complete fossil palaeontinids in the Middle Jurassic of the world. Based on observation of these new specimens, Sc of this new genus has the following combined characters: joined with R at base, diverged near M separation, coalesced with R before the nodal line, extended beyond the nodal line and fused with R-1 before distal end. Due to the Sc characteristics mentioned above, the genus Liaocossus Ren, Yin and Dou, 1998 can be well distinguished from "Ilerdocosus-complex".