This paper shows that the etymological practice of adding, subtracting, substituting and transposing letters within a name, attested since Plato’s Cratylus, was already in use in Greek mythography. I discuss two mythographical passages, more or less coeval to the Cratylus, where the etymologies under examination involve an ‘intermediary form’, as words have a history of their own and may have undergone some modifications in the passage of time. These two cases of ‘etymology through corruption’ (κατὰ φθοράν or κατὰ παραφθοράν) are ascribed to Andron of Teos (FGrHist 802 F3) and Andron of Halicarnassus (fr. 8 EGM) respectively, and I incidentally suggest that both texts belong to Andron of Teos.
