Harpocration[18] tells us that Apollodorus devoted the sixth book of his treatise _Concerning the gods_ to the discussion of the θεοὶ ἀποπομπαῖοι, the gods of Sending-away. The loss of this treatise is a grave one for the history of ritual, but scattered notices enable us to see in broad outline what the character of these gods of Aversion was. Pausanias[19] at Titane saw an altar, and in front of it a barrow erected to the hero Epopeus, and ‘near to the tomb,’ he says, ‘are the gods of Aversion, beside whom are performed the ceremonies which the Greeks observe for the averting of evils.’ Here it is at least probable, though from the vagueness of the statement of Pausanias not certain, that the ceremonies were of an underworld character such as it will be seen were performed at the graves of heroes. The gods of Aversion by the time of Pausanias, and probably long before, were regarded as gods who presided over the aversion of evil; there is little doubt that to begin with these gods were the very evil men sought to avert. The domain of the spirits of the underworld was confined to things evil. Babrius[20] tells us that in the courtyard of a pious man there was a precinct of a hero, and the pious man was wont to sacrifice and pour libations to the hero, and pray to him for a return for his hospitality. But the ghost of the dead hero knew better; only the regular Olympians are the givers of good, his province as a hero was limited to evil only. He appeared in the middle of the night and expounded to the pious man this truly Olympian theology: ‘Good Sir, no hero may give aught of good; For _that_ pray to the gods. We are the givers Of all things evil that exist for men.’ It will be seen, when we come to the subject of hero-worship, that this is a very one-sided view of the activity of heroes. Still it remains, broadly speaking, true that dead men and the powers of the underworld were the objects of fear rather than love, their cult was of ‘aversion’ rather than ‘tendance.’ A like distinction is drawn by Hippocrates[21] between the attributes, spheres and ritual of Olympian and chthonic divinities. He says: ‘we ought to pray to the gods, for good things to Helios, to Zeus Ouranios, to Zeus Ktesias, to Athene Ktesia, to Hermes, to Apollo; but in the case of things that are the reverse we must pray to Earth and the heroes, that all hostile things may be averted.’