Zeus, in recognition of their familial love, took pity upon them and changed them into stars—the constellation Hyades—and placed them in the head of Taurus, where their annual rising and setting are accompanied by plentiful rain.
And his death gave these weepy rain-nymphs a cause for their weeping, mourning for a male being an acceptably passive female role in the patriarchal culture of the Hellenes.
[9] Hyas had no separate existence except as progenitor/guardian of the Hyantes, neither in mythic narrative nor in rite, even the alternative accounts of his demise being somewhat conventional and interchangeable: compare the death of Meleager or Actaeon.
The Hyantes, descendants of Hyas—or rather of the Hyades, for the fertility of rain-nymphs needs no male consort— were the original ("Pelasgian") inhabitants of Boeotia, from which country they were expelled by the followers of Cadmus.
The poets used the adjective Hyantius as equivalent to Boeoticus, or "rural", partly as a demonstration of how conversant they were with such arcane details: The speaker is Actaeon, grandson of Cadmus, who came to an end somewhat similar to that of Hyas.