An apparatus on a flat card or roller card for textile fibres, wherein a covering comprising work and cover elements lies opposite clothing of a high-speed cylinder, in which, viewed in a direction of rotation of the cylinder, in succession there is an opening for the exit of air (exhaust airflow) and an opening for entry of air (supply airflow), past which openings a flow of fibres and air is passed, wherein, in relation to the cylinder, the spacing of the covering upstream of the exhaust air opening and the spacing of the covering downstream of the exhaust air opening are different, wherein in relation to the cylinder the spacing of the covering upstream of the exhaust opening is smaller than the spacing of the covering between exhaust air opening and supply air opening and an air flow that detaches short fibres from the flow of fibres flows along a surface of the cylinder against the direction of rotation of cylinder and flows away with short fibres through the exhaust air opening.