From the scholia to Aristophanes, Knights 1381, where the headword adjective uniquely occurs (web address 1). Translation here follows the scholiast's interpretative lead, though it is not necessarily correct. Given an instance in Lucian, J. Henderson, The Maculate Muse (New Haven 1975) seems wrong to restrict the 'anus' sense of daktu/lion to technical writers (he ignores katadaktuliko/s altogether), but even so it is possible that the actual etymology of the adjective focuses on obscene use of the fingers rather than the orifice they enter. For this interpretation see Sommerstein's translation at phi 152.