Folly refers to the story of Midas, whose ears were changed by Apollo into those of an ass for preferring Pan's flute to Apollo's lyre (Ovid, Metamorphoses, II, 153 ff. and Herodotus, 7, 33). Midas was at some pains to hide his ears, but his barber betrayed him. There is another reference to Midas in the Adages.