ἐν τῷ θέρει τὴν χλαῖναν κατατρίβων → wearing out one's cloak in summertime
subs.
P. μῖλαξ, ἡ (Plat.).
The word is also found in Eur., Bacch. 703, and Aristophanes, Nub. 1007, but apparently with a different meaning.
