in fabulous history, an Italian shepherd upon Mount Aventine. As Hercules was driving home the herd of King Geryon, whom he had slain, Cacus robbed him of some of his oxen, which he drew backward into his den lest they should be discovered. Hercules at last finding them out by their lowing, or the robbery being otherwise discovered to him, killed Cacus with his club. He was Vulcan's son, of prodigious bulk; and half man half satyr.