Syrinx, an Arcadian Nymph, who was loved by Pan. The god pursued her, but just as he was about to catch her, she changed herself into reed on the banks of the Ladon river. Pan picked up the reeds and joined together the stems of different length. Thus he got a musical instrument, which he called the Syrinx, in memory of the Nymph.
See: Jacob Jordaens. Pan and Syrinx.
Nicolas Poussin Nymph Syrinx Pursued by Pan.