Passage 9.5.11
μητέρα τʼ Οἰδιπόδαο ἴδον, καλὴν Ἐπικάστην, ἣ μέγα ἔργον ἔρεξεν ἀιδρείῃσι νόοιο γημαμένη ᾧ υἱεῖ· ὁ δʼ ὃν πατέρʼ ἐξεναρίξας γῆμεν· ἄφαρ δʼ ἀνάπυστα θεοὶ θέσαν ἀνθρώποισιν. Hom. Od. 11.271 πῶς οὖν ἐποίησαν ἀνάπυστα ἄφαρ, εἰ δὴ τέσσαρες γενεαὶ ἐκ τῆς Ἐπικάστης ἐγένοντο παῖδες τῷ Οἰδίποδι; ἐξ Εὐρυγανείας δὲ τῆς Ὑπέρφαντος ἐγεγόνεσαν. δηλοῖ δὲ καὶ ὁ τὰ ἔπη ποιήσας ἃ Οἰδιπόδια ὀνομάζουσι· καὶ Ὀνασίας Πλαταιᾶσιν ἔγραψε κατηφῆ τὴν Εὐρυγάνειαν ἐπὶ τῇ μάχῃ τῶν παίδων.
I saw the mother of Oedipus, fair Epicaste, who unwittingly performed a great deed when she married her own son. He, after slaying his father, married her; but straightway the gods made these matters notorious among the people (Homer, Odyssey, 11.271). But how, then, did they make it immediately notorious if indeed four children born to Oedipus came from Epicaste? In fact, they were born from Euryganeia, daughter of Hyperphas. This is also made clear by the poet who composed the verses called the Oedipodeia, and Onasias likewise portrayed Euryganeia at Plataea in grief over the battle of her sons.