A bugle is a simple brass instrument, similar to a trumpet but with no valves. Because it is unvalved, the bugle can only play a limited range of notes and is thus not suitable for use in orchestras, though it is common in brass bands and military bands.
Bugles are often used to play loud fanfares, announcing the arrival of an important guest. In former times, messengers often used bugles to herald their presence, which is presumably why 'bugle' is a common name for newspapers (e.g. "The Daily Bugle").