In classical mythology, Hylas was a youth who served Heracles as companion and arms-bearer. Son of King Theiodamas of the Dryopians and the nymph Menodice (with variant fathers in some notices), he sailed with the Argonauts and was abducted by water nymphs at a Mysian spring — an enduring theme in ancient and later art.
Adapted from Wikipedia, "Hylas" · CC BY-SA 4.0
I.Genealogy
Most accounts make Hylas son of Theiodamas (Theodamas) of the Dryopians and Menodice, a nymph daughter of Orion. Alternatives name Heracles, Euphemus, or King Ceyx of Trachis as his father. After Heracles killed Theiodamas in battle, he took the boy as arms-bearer and taught him to fight.
Theocritus' Idyll 13 celebrates Heracles' love for the curly-haired youth, comparing it to a father's care for a dear son.
II.Abduction in Mysia
Heracles brought Hylas on the Argo. At the spring of Pegae in Mysia, naiads fell in love with him and drew him into the water. Heracles and Polyphemus searched long; the ship sailed without them. Valerius Flaccus has Hylas remain willingly with the nymphs; Apollonius has Glaucus tell the Argonauts a nymph has made him her husband; Theocritus has the nymphs stifle his cries underwater; Antoninus Liberalis turns him into an echo that answers Heracles' shouts.
The lost-boy search became a stock image of mourning beauty in later literature and painting.
III.Reception
Hylas recurs from Spenser and Marlowe to Oscar Wilde, Hardy, and Waterhouse's Hylas and the Nymphs; he also appears in the 1963 film Jason and the Argonauts. The mythic figure should not be confused with the materialist interlocutor of Berkeley's Three Dialogues.
In this atlas he is the Argonaut beloved of Heracles.