Singer and piano player from Chester, Pennsylvania, member of The McCoys. Sang it as "there's a fly on baby's head". In his Creeper's Blues (Vocalion - 1929) the late Memphis bluesman Furry Lewis sings: "Mama get your hatchet, there's a fly on the baby's head".
According to Barrence only an American can come up with lyrics like these. Walter Bishop also wrote Jack You're Dead and Swing, Brother, Swing (see there). Also: If You're So Smart (How Come You Ain't Rich), Everything That's Made Of Wood (Was Once A Tree) and Every Floor Has A Ceiling (And Every Ceiling Has A Floor).