Alcmaeon. I. In ancient Greek legends, a son of Amphiaraus and Eriphyle of Argos, and brother of Amphilochus. Eriphyle having been bribed by Polynices with the necklace and robe of Harmonia to induce Amphiaraus to join the expedition of the seven against Thebes, the latter, foreseeing that he should fall, charged his sons to kill her when they were grown up. Meantime, an oracle having declared that the expedition of the epigoni would be successful if commanded by Alcmseon, Polynices again bribed Eriphyle with the peplus of Harmonia to persuade him to comply. On his return Alcmaeon fulfilled his father's injunction by killing her. For this crime he was afflicted with madness and tormented by the Furies, who drove him into exile, and doomed him to a life of perpetual wandering. Arriving in Psophis, he was hospitably received and purified by its king, Phe-geus, who gave him his daughter Arsinoe in marriage. To her Alcmaeon presented the necklace and robe of Harmonia. But Psophis having been visited by a famine because of Alcmaeon's sojourn there, he had to depart, and, by the advice of an oracle, went to the land of the river god Achelous, where he married the nymph Calirrhoe. His new spouse coveting the magical robe and necklace which he had given to Arsinoe, Alcmaeon went to Psophis and obtained them from the daughter of Phegeus, under the pretence that he was going to dedicate them at Delphi. But when Phegeus heard that they had been presented to Calirrhoe, he sent his sons to slay Alcmaeon and avenge the insult offered to their sister.

Alcmaeon was afterward worshipped as a hero in many parts of Greece.

II. A Greek natural philosopher, born in the Hellenic city of Cro-tona in southern Italy, about the middle of the 6th century B. C. He is said to have studied under Pythagoras, and to have been the first who ventured on the practice of dissecting animals. He wrote several medical and philosophical treatises, of which a few fragments remain.