PHILADELPHIA — A rare violin worth $172,000 that was mistakenly left on a Boston-to-Philadelphia bus by a groggy music student has been found and returned to its owner.

Megabus USA director Bryony Chamberlain said Friday that a cleaning crew recovered the instrument. The New England Conservatory student got on a Megabus in Boston with the 176-year-old violin but got off without it late Tuesday, police said.

The 19-year-old student, Muchen Hsieh, told investigators that she left the instrument in an overhead bin and only realized she had forgotten it after she had been picked up. The violin was lent to her by the Chi Mei Culture Foundation in her native Taiwan.

Megabus offers low-cost express bus service to more than 70 cities.