Definition and background:
The marching version of a glockenspiel in the shape of a lyre. When used in a marching band it is held upright and supported by a strap around the performer's waist. Also known as a bell lyra.
For more information on the music term "Bell lyre" check out these other resources:
Wikipedia - Glossary of Musical Terminology
Virginia Tech Multimedia Music Dictionary
ORB -- Medieval Music Glossary