Leader of the Epigoni, and son of Amphiaraus and Eriphyle. Eriphyle hade made her husband take part in the war against Thebes, and after he was killed she made her son do the same.
Alcmaeon went to the oracle of Delphi, and was told to kill his mother. After he had commited the matricide, he went insane, and the punishing goddesses Erinyes haunted him.
Finally Alcmaeon came to king Psophis of Arcadia, where he married the king's daughter Arsinoe. Arcadia went barren because of Alcmaeons presence and he then fled to the river Anchelous and married the river-god's daughter Callirhoe.
King Psophis and his sons eventually caught up with Alcmaeon and killed him.