EN
Eoiocossus validas gen. and sp. nov., a new genus and species belonging to Palaeontinidae (Insecta, Hemiptera), is described from the Middle Jurassic of Daohugou, Inner Mongolia, China. It differs from other genera as follows: large forewing with small clavus, Sc terminating in costal margin beyond the nodus, nodal line along m₄ -cua partly, CuA₂ with two branches and A₂ developed. The ripple-like posterior margin and fresh colour pattern of Eoiocossus may be sex characteristics. The marginal membrane and ambient vein have not distinct evolutionary implications for the Palaeontinidae.