Passage 2.19.8
τάφοι δέ εἰσιν ὁ μὲν Λίνου τοῦ Ἀπόλλωνος καὶ Ψαμάθης τῆς Κροτώπου, τὸν δὲ λέγουσιν εἶναι Λίνου τοῦ ποιήσαντος τὰ ἔπη. τὰ μὲν οὖν ἐς τοῦτον οἰκειότερα ὄντα ἑτέρῳ λόγῳ παρίημι τῷδε, τὰ δὲ ἐς τὸν Ψαμάθης ἡ Μεγαρική μοι συγγραφὴ προεδήλωσεν. ἐπὶ τούτοις ἐστὶν Ἀπόλλων Ἀγυιεὺς καὶ βωμὸς Ὑετίου Διός, ἔνθα οἱ συσπεύδοντες Πολυνείκει τὴν ἐς Θήβας κάθοδον ἀποθανεῖσθαι συνώμοσαν, ἢν μὴ τὰς Θήβας γένηταί σφισιν ἑλεῖν. ἐς δὲ τοῦ Προμηθέως τὸ μνῆμα ἧσσόν μοι δοκοῦσιν Ὀπουντίων εἰκότα λέγειν, λέγουσι δὲ ὅμως.
There are tombs, one of Linus, the son of Apollo and Psamathe, daughter of Crotopus, and another tomb said to belong to Linus who composed the poetry. Matters concerning the latter Linus, being more appropriately dealt with elsewhere, I omit from the present account, but concerning Psamathe, this topic was previously covered in my description of Megara. Near these monuments stands a statue of Apollo Agyieus and an altar dedicated to Zeus Hyetius, where those who joined Polynices in his march upon Thebes swore an oath to perish if they did not succeed in taking the city. As to the tomb of Prometheus, the account of the Opuntians seems to me less credible, though they relate it nonetheless.