BUCO´LION(Βουκολιών), a place in Arcadia of uncertain site, to which the Mantineians retreated, when they were defeated by the Tegeatae in B.C. 423. But as the battle was probably fought in the valley of the Alpheius, near the spot where Megalopolis was afterwards built, Bucolion must have been somewhere in this neighbourhood. (Thuc. 4.134, with Arnold's note.)