(Μελήσιππος), a Lacedaemonian, son of Diacritus, was one of the three ambassadors sent to Athens in B. C. 432, just before the commencement of the Peloponnesian war, with the final demand of Lacedaemon for the restoration of the independence of all the Greek states. By the advice of Pericles, the Athenians refused compliance. In the following year, when Archidamus was on his march to invade Attica, be again sent Melesippus to Athens, in the hope of effecting a negotiation; but the Athenians would not even admit him to a hearing. (Thuc. 1.139_145, 2.12.)