The Manes are the spirits of the dead. They inhabit the underworld and occasionally visit the living. They had festivals to placate them: the Feralia, the Lemuria, and the Parentalia. Sacrifices were given to them on graves decorated with wreaths of lilies, roses, and violets. The most common sacrifices were milk, honey, oil, wine, and the blood of black animals.
Di Manes: "The Divine Dead"