A son of Onchestus, is also called a son of Poseidon by Oenope, of Hippomenes, Apollo, or Aegeus. (Apollod. iii. 15. § 8; Paus. i. 39. § 5; Ov. Met. x. 605; Hygin. Fab. 157; Steph. Byz. s. v. Megara.) He was a brother of Abrote, the wife of Nisus, and the father of Euippus, Timalcus, and Euaechme, to whom Ovid adds a fourth, Hippomenes. (Paus. i. 41. § 4; Plut. Quaest. Graec. 16.) According to a Boeotian tradition, Megareus with his army went to the assistance of Nisus, king of Megara, against Minos ; but he fell in battle, and was buried at Megara, which was called after him, for its previous name had been Nisa. (Apollod. l. c.; Paus. i. 39. § 5, 42. § 1.) According to a Megarian tradition, which discarded the account of an expedition of Minos against Megara, Megareus was the husband of Iphinoë, the daughter of Nisus, and succeeded his father-in-law in the government of Megara, which he left to Alcathous, because his own two sons had died before him. (Paus. i. 39. § 5; comp. ALCATHOUS.)