Two new genera with two new species of sawflies,Cathayxyela extensa gen.et sp.nov.and Aequixyela immensa gen.et sp.nov.,from the Middle Jurassic Jiulongshan Formation of southeastern Inner Mongolia,China,are assigned to the subfamily Xyelinae(Hymenoptera,Xyelidae).Cathayxyela gen.nov.can be distinguished by the third antennal article longer than the head; mesoprescutum and mesoscutellum nearly equal in length; the forewing with Sc meeting C before the junction of 1-M and 1-Rs; a weak and narrow pterostigma; and 3-Cu at least 1.5 times longer than the 1m-cu.Aequixyela gen.nov.is characterized by the third antennal article nearly as long as the head; the forewing with Rs+M approximately equal to 2-Rs in length; 2m-cu inclined toward the wing base and nearly reaching the middle of cell 3rm; 1m-cu as long as the 2-Cu and 3-Cu; and the cell 2cua of regular hexagonal shape. Two new genera with two new species of sawflies, Cathayxyela extensa gen.et sp.nov.and Aequixyela immensa gen.et sp.nov., From the Middle Jurassic Jiulongshan Formation of southeastern Inner Mongolia, China, are assigned to the subfamily Xyelinae ( Hymenoptera, Xyelidae) .Cathayxyela gen.nov.can be distinguished by the third antennal article longer than the head; mesoprescutum and mesoscutellum nearly equal in length; the forewing with Sc meeting C before the junction of 1-M and 1-Rs; a weak and narrow pterostigma; and 3-Cu at least 1.5 times longer than the 1m-cu.Aequixyela gen.nov.is characterized by the third antennal article nearly as long as the head; the forewing with Rs + M approximately equal to 2- Rs in length; 2m-cu inclined toward the wing base and almost reached the middle of cell 3rm; 1m-cu as long as the 2-Cu and 3-Cu; and the cell 2cua of regular hexagonal shape.