(Μενυλκίδας), a Lacedaemonian adventurer, who, in some way not further specified by Polybius, took advantage of the circumstances of Egypt, in its war with Antiochus Epiphanes (B. C. 171-168), to advance his own interests at the Ptolemies' expence. He was thrown into prison by Philometor and Physcon, but was released by them in B. C. 168, at the request of C. Popillius Laenas, the Roman ambassador, who was sent to command Antiochus to withdraw from the country. (Plb. 30.11; comp. Liv. 45.12, 13; Just. 34.2, 3; V. Max. 6.4.3.) In B. C. 150 we find Menalcidas, as general of the Achaean league, engaging for a bribe of ten talents to induce the Achaeans to aid Oropus against Athens. By the promise of half the sum, he won Callicrates to the same cause, and they succeeded in carrying a decree for the succour required. No effectual service, however, was rendered to the Oropians, but Menalcidas still exacted the money he had agreed for, and then evaded the payment of his portion to Callicrates. The latter accordingly retaliated on him with a capital charge of having attempted to prevail on the Romans to sever Sparta from the league; and Menalcidas only escaped the danger through the protection of Diaeus, which he purchased with a bribe of three talents. [CALLICRATES, No. 4.] In B. C. 149 he supported at Rome, against Diaeus, the cause of the Lacedaemonian exiles. [DIAEUS.] In B. C. 147, when the war between the Achaeans and Lacedaemonians had been suspended at the command of Caecilius Metellus, he persuaded his countrymen to break the truce, and seized and plundered Iasus, a subject town of the Achaeans on the borders of Laconia. The Lacedaemonians, soon repenting of their rashness, were loud in their outcry against their adviser; and he, driven to despair, put an end to his own life by poison, "having shown himself," says Pausanias, "as leader of the Lacedaemonians at that time, the most unskilful general; as leader of the Achaeans formerly, the most unjust of men." (Plb. 40.5; Paus. 7.11, 12, 13, 16.)