Passage 9.26.2
προελθόντων δὲ τὸ ὄρος ἐστὶν ὅθεν τὴν Σφίγγα λέγουσιν ὁρμᾶσθαι ἐπʼ ὀλέθρῳ τῶν ἁρπαζομένων αἴνιγμα ᾄδουσαν· οἱ δὲ κατὰ λῃστείαν σὺν δυνάμει ναυτικῇ πλανωμένην φασὶν αὐτὴν ἐς τὴν πρὸς Ἀνθηδόνι σχεῖν θάλασσαν, καταλαβοῦσαν δὲ τὸ ὄρος τοῦτο ἁρπαγαῖς χρῆσθαι, πρὶν ἐξεῖλεν Οἰδίπους αὐτὴν ὑπερβαλόμενος πλήθει στρατιᾶς ἣν ἀφίκετο ἔχων ἐκ Κορίνθου.
As one proceeds, there is a mountain from which they say the Sphinx launched herself, singing forth her riddle to the ruin of those she carried off. But others assert that, living as a pirate, she wandered about with a naval force, and landed at the sea near Anthedon, and occupied this mountain, engaging in acts of robbery, until Oedipus overcame her, surpassing her in battle with a greater force, which he brought with him from Corinth.