This fragment, and another in the same case (18.104.22.168, .8), belongs to a volute-krater that depicted the death of Pentheus on the obverse and the battle of gods and Titans on the reverse. The piece shows the winged horse looking back at Bellerophon, whose left hand appears holding one rein. To the right is Zeus seated in his chariot. The bit of wing belongs to a figure of Nike.
Mayo, Margaret Ellen and Kenneth Hamma. 1982. The Art of South Italy: Vases from Magna Graecia no. 33, p. 110, 112, 207, 309, Richmond: Virginia Museum of Fine Arts.