Upius

A Mariandynian and king of Bithynia whose son, Bormus, a youth distinguished for his extraordinary beauty, was drawn into a well by the nymphs and never seen again.
(Athen. xiv. p. 620; Aeschyl. Pers. 941; Schol. ad Dionys. Periey. 791; Pollux, iv. 54.

From The Golden Bough : A Study Of Magic and Religion

In Bithynia a like mournful ditty, called Bormus or Borimus, was chanted by Mariandynian reapers. Bormus was said to have been a handsome youth, the son of King Upias or of a wealthy and distinguished man. One summer day, watching the reapers at work in his fields, he went to fetch them a drink of water and was never heard of more. So the reapers sought for him, calling him in plaintive strains, which they continued to chant at harvest ever afterwards.