Street musicians: the flute player (photo courtesy of VRoma)

The tibicen was the musician who played the tibia, a double pipe. Double-reed wind instruments appear in images from Mesopotamia as early as 3,000 BC. The flute was the first wind instrument used by the Egyptians and the one most commonly used by the Greeks, Etruscans, and Romans (see Musica Romana). The Greeks attributed its invention to Pan, the god of flocks and shepherds, who found the reed, its earliest material, abundant in the fields; ancient pipes have been found in a variety of materials (bone, ivory, and metal) and styles (e.g., the aulos was a single hollow reed which became popular as a double pipe), each instrument producing a distinctive sound. The most popular of the wind instruments was the tibia, which consisted of two pipes, each with a mouthpiece at the top and holes pierced in the stems, and was played with two hands. It was used in religious ceremonies, rituals and the theatre (the comedies of Terence were accompanied by pipes of several kinds).
Umbricius is no doubt making reference to imported flute-girls, popular entertainers at parties who arrived in Rome from the 2nd century BCE in the wake of military campaigns in the East.