Mantius (Ancient Greek Μαντίος, "diviner, seer") was a son of the Argive seer Melampus and Iphianassa, brother of Antiphates, and father of Cleitus and Polypheides — whom Apollo made the greatest mortal seer after Amphiaraus. Some versions also name him father of Oicles.
Adapted from Wikipedia, "Mantius" · CC BY-SA 4.0
I.Melampodid line
In the Odyssey Melampus' son Mantius fathers Cleitus — whom Dawn snatches for his beauty — and Polypheides, whom Apollo sets as chief seer among mortals once Amphiaraus is dead. Apollodorus keeps Mantius in the same Melampodid stem at Argos.
Pausanias preserves related Melampodid local lore; the name itself advertises the family's mantic vocation.
II.Homonym care
Mantius is also a genus of jumping spiders — irrelevant to the mythic node. The atlas id mantius-melampid is Melampus' Argive son alone.