Abstract: A device comprises a guide cover extending from above the taker-in roller on one side of the cylinder toward and over a feed roller and defining a passage for the air stream produced by the rotation of the taker-in roller to return fibers entrained in the air stream onto a lap on the dish plate. The guide cover is provided with auxiliary guide plates disposed within the passage and extending respectively from the opposite side walls of the guide cover toward the center of the passage while slanting toward the direction of advance of the air stream with respect to the axis of the taker-in roller when seen in plan, each of the guide plates being provided with a guide face having a progressively reducing width toward its forward end. A control roller is disposed between the guide cover and the cylinder and positioned close to the periphery of the cylinder and the periphery of the taker-in roller.