It was a simple wind instrument, forerunner of the flute.

It consisted of one long bone, cane, or metal tube, open or closed at one end, with one or more finger-holes. It did not have a reed and the player held it sideways on his lips to the left, and blew directly into its open end.

There was also a variation of this instrument where the blowing was executed from a special hole on the side (“plagiaulos”).

SOURCES: M.L. West, Ancient Greek Music, Curt Sachs, The History of Musical Instruments, Julius Pollux, Onomasticon, Apollodorus, The Library, Aristotle, (Musical) Problems, Plutarch, On Music, Athenaeus of Naucratis, Deipnosophistai, Theokritos, Bukolika.