Abstract: A riding mower (1) comprising a cutting device (6) which moves cut grass through a rearwardly extending connection conduit (6) into a rear collector (7) for cut grass, and wherein for emptying, the collector (7) is pivotally mounted and adapted to be detached from the connection conduit (6). A movable flap (8) is disposed in the region of the connection conduit (6) and in one embodiment is mounted on the collector (7) and upon disengagement of the collector (7) from the connection conduit (6) and pivoting the collector (7), the flap (8) can be moved into a position closing the collector (7). In another embodiment, the flap (8) is mounted on the connection conduit (6) and at least the portion of the connection conduit (6) on which the flap is mounted follows the movement of the collector (7) during emptying of the collector (7).