Young Dionysus and the Hyades

In Greek mythology, two different groups of people were referred to as the Hyades (Ὑάδες) ("the rainy ones"). Pluvius ("he who sends rain") was also used to describe them.

Sisters of Hyas. Their brother was accidentally killed in a hunting accident and the Hyades died from their grief. They were changed into stars, the head of Taurus. Their names are Phaola, Ambrosia, Eudora, Coronis, and Polyxo.

Additionally, Thione and Prodice, who were supposed to be daughters of Hyas by Aethra (one of the Oceanides), have been added to the group of stars.

There he hammered out the earth, the heavens, the sea,                   
the untiring sun, the moon at the full, along with
every constellation which crowns the heavens—
the Pleiades, the Hyades, mighty Orion,
and the Bear, which some people call the Wain,
always circling in the same position, watching Orion,
the only stars that never bathe in Ocean stream. Iliad, Book 18

The Greeks believed that the rising and setting of the Hyades stars were always attended with rain, hence the association of the Hyades (sisters of Hyas) and the Hyades (daughters of ocean) with the constellation of the Hyades (rainy ones) and called also 'huo pluo'/'pluvius' (the rain bringer).

According to some, Hyades are the daughters of Atlas and sisters of the Pleiades. The best accounts, however, make them to have been the nymphs of Dodona, to whom Zeus confided the nurture of Bacchus. Pherecydes gives their names as Ambrosia, Coronis, Eudora, Dione, Aesula, and Polyxo. Hesiod, on the other hand, calls them Phaesula, Coronis, Cleea, Phaeo, and Eudora. The names generally given to the seven stars are Ambrosia, Eudora, Pedile, Coronis, Polyxo, Phyto, and Dione or Thyene. The Hyades went about with their divine charge, communicating his discovery to mankind, until, being chased with him into the sea by Lycurgus, Zeus, in compassion, raised them to the skies and transformed them into stars. According to the more common legend, however, the Hyades, having lost their brother Hyas, who was killed by a bear or lion, or, as Timaeus says, by an asp, were so disconsolate at his death that they pined away and died; and after death they were changed into stars ( Hyg. Fab.192). The stars called Hyades (Ὑάδες) derived their name from ὕειν, “to make wet,” “to rain,” because their setting, at both the evening and morning twilight, was for the Greeks and Romans a sure presage of wet and stormy weather, these two periods falling respectively in the latter half of April and November. Horace, with a double allusion to both fable and physical phenomena, calls the stars in question tristes Hyadas ( Carm.i. 3 Carm., 14). The Roman writers sometimes call these stars by the name of Suculae, “little pigs,” for which epithet Pliny assigns a singular derivation. According to this writer, the Roman farmers mistook the etymology of the Greek name Hyades, and deduced it, not from ὕειν, “to rain,” but from ὗς, “a sow” (Pliny , Pliny H. N.xviii. 26). It is more probable, however, that Suculae was the oldest Roman name, given before the Greek appellation was known, and to be compared with our popular astronomical terms such as “the Dipper,” “Charles's Wain,” etc. Isidorus derives the term Suculae from succus, in the sense of “moisture” or “wet” (a succo et pluviis, Isidor. Orig.iii. 70), an etymology which has found its way into many later works. Some grammarians, again, sought to derive the name Hyades from the Greek Υ (upsilon), in consequence of the resemblance which the cluster of stars bears to that letter.