"Melampus was a man of exceptional piety and became a friend of Apollo."
(Const.Exc 2(1) p.211)
Melampus begot Antiphates and Mantius. Antiphas sired great-hearted Ocicles, in turn the father of Amphiaraus "whom Zeus...and Apollo heartily loved in all manners of ways."(Od 15.238). Amphiaraus was dear to the gods and did not die but was enfolded in Gaea's bosom as he fled the defeat of the seven against Thebes (Statius, Thebiad 8.329).
Amphiaraus left behind two sons Alcmaeon and Amphilocus. Amphilocus becomes a god according to Lucian (DD 10.). Meanwhile his cousin Cleitus, son of Mantius, son of Melampus "golden-throned Dawn snatched away by reason of his beauty that he might dwell with the immortals." od 15.238
So here is the lineage of Melampus, a man of exceptional piety. We have no record of his descendants' piety, but several were dear to the gods or made immortal. Though not meeting these specific criteria, other Melampides were obviously favored by the gods. So was it good genes, good upbringing or good reputation for their family that made so many of them dear to the gods?
Previous segments of this discussion include;
Part II: The Trojans Princes