Lewis & Short

Hylas, ae, m., = Ὕλας, a beautiful youth of Œchalia (or Argos), companion of Hercules in the Argonautic expedition, who was carried off by the nymphs, and long sought for by Hercules in vain, Prop. 1, 20, 6; Ov. A. A. 2, 110; Juv. 1, 164; Val. Fl. 3, 596; Hyg. Fab. 14; Verg. E. 6, 44 (where, by poet. license, the voc. is scanned Hylā, Hȳl’, like the Gr. Ἆρες, Ἄρες, Mart. 9, 11, 15).