Discussion of formation and accentuation of adjectives in -ειος (examples: Ἠλεῖος/Ἠλίειος, Κρῆτειος, Μήδειος), note on proparoxytone preaccentuation, alternations, and a Callimachus citation.
ῥαγδαῖος, σταδαῖος, ἀδαῖος, Ἀγκαῖος παρὰ τὸ ἀγκάς. τὸ μέντοι μάτην μάταιος, τὸ δήν δηναιός, τὸ πάλαι παλαιός. Τὰ ἀπὸ ῥημάτων περισπῶνται, βέβαιος παρὰ τὸ βέβηκα, Φίλαιος, Νίκαιος, Τίμαιος, Λύαιος, Πείραιος, Πήδαιος· οὐ γὰρ τοῦτο, ὡς οἴεται ὁ Ἅβρων, παρὰ τὴν πῆδον (?)· ἐοικὸς γὰρ μᾶλλον ἥρωϊ παρὰ τὸ πηδᾶν ἐσχηματίσθαι. Τὰ εἰς 'ειος' καθαρὸν τρισύλλαβα ἔχοντα ἐν τῇ τρίτῃ 'η' προπαροξύνεται, θήρειος, μήλειος, χήνειος, κήλειος ὁ καυστικός, Κρήτειος. τὸ μέντοι Ἠτεῖος—ἦν δὲ Ἠτεῖος εἷς τῶν ἑπτὰ σοφῶν, ὡς Δίδυμος συμποσιακῶν δεκάτῳ, Πλάτων δὲ ἐν Πρωταγόρᾳ Χηνέα τοῦτον εἶπεν—Ἠλεῖος, ἠθεῖος προπερισπᾶται οὐκ ἀπὸ συμφώνου ἀρχόμενα. καὶ τὸ μὲν Ἠλεῖος οὕτω γίνεται· ἀπὸ τῆς Ἤλιδος γενικῆς ἀναλόγως Ἠλίδειος ὡς Ἀδωνίδειος καὶ Εὐπολίδειος κτητικῷ τύπῳ καὶ καθ´ ὕφεσιν τοῦ 'δ' Ἠλίειος καὶ Ἠλεῖος, ἀφ´ οὗ «Ἀλεῖος Ζεύς» (Callim. fr. 99). Τρύφων δέ φησιν, ὅτι Ἠλίεος καὶ Ἠλέϊος καὶ Ἠλεῖος. τὸ δὲ ἠθεῖος ἴσως παρὰ τὸ θεῖος, λέγω δὲ τὸ σημαντικὸν τοῦ ἐπαίνου, κατὰ πλεονασμὸν τοῦ 'η' ἐγένετο. Τὸ δὲ Κητειός, Πηνειός ὀξύνεται ὡς κύρια. καὶ τὸ Μήδειος κύριον—ἔστι δὲ ἔθνος ὃ καὶ Μῆδοι—προπαροξύνεται καθάπερ Βούδειοι ἔθνος Μηδικόν.
ῥαγδαῖος, σταδαῖος, ἀδαῖος, Ἀγκαῖος from ἀγκάς. But μάταιος from μάτην, δηναιός from δήν, παλαιός from πάλαι. Forms derived from verbs are circumflexed: βέβαιος from βέβηκα, Φίλαιος, Νίκαιος, Τίμαιος, Λύαιος, Πείραιος, Πήδαιος; for it is not this, as Habron thinks, from πῆδον (?); rather it is likely to have been formed in heroic fashion from πηδᾶν. The pure trisyllables in -ειος that have η in the third syllable are accented on the antepenult: θήρειος, μήλειος, χήνειος, κήλειος ‘the caustic’, Κρήτειος. But Ἠτεῖος—now Ἠτεῖος was one of the Seven Sages, as Didymus says in the tenth book of his Symposiaca, while Plato in the Protagoras called this man Χηνέας—Ἠλεῖος, and ἠθεῖος take a circumflex on the prepenult, since they do not begin with a consonant. And Ἠλεῖος comes about thus: from the genitive of Ἦλις, by analogy Ἠλίδειος, as Ἀδωνίδειος and Εὐπολίδειος in the possessive type, and by loss of δ, Ἠλίειος and Ἠλεῖος, from which comes “Ἀλεῖος Ζεύς” (Callim. fr. 99). But Tryphon says that the forms are Ἠλίεος and Ἠλέϊος and Ἠλεῖος. And ἠθεῖος perhaps arose from θεῖος—I mean the one signifying praise—by addition of η. But Κητειός and Πηνειός are accented with an acute, as proper names. And the proper name Μήδειος—there is a people also called Μῆδοι—is accented on the antepenult, just as Βούδειοι, a Median people.