Passage 1.22.7
ἵππων δέ οἱ νίκης τῆς ἐν Νεμέᾳ ἐστὶ σημεῖα ἐν τῇ γραφῇ· καὶ Περσεύς ἐστιν ἐς Σέριφον κομιζόμενος, Πολυδέκτῃ φέρων τὴν κεφαλὴν τὴν Μεδούσης. καὶ τὰ μὲν ἐς Μέδουσαν οὐκ εἰμὶ πρόθυμος ἐν τοῖς Ἀττικοῖς σημῆναι· ἔτι δὲ τῶν γραφῶν παρέντι τὸν παῖδα τὸν τὰς ὑδρίας φέροντα καὶ τὸν παλαιστὴν ὃν Τιμαίνετος ἔγραψεν, ἐστὶ Μουσαῖος. ἐγὼ δὲ ἔπη μὲν ἐπελεξάμην, ἐν οἷς ἐστι πέτεσθαι Μουσαῖον ὑπὸ Βορέου δῶρον, δοκεῖν δέ μοι πεποίηκεν αὐτὰ Ὀνομάκριτος καὶ ἔστιν οὐδὲν Μουσαίου βεβαίως ὅτι μὴ μόνον ἐς Δήμητρα ὕμνος Λυκομίδαις.
In the painting there are also indications of his victory with horses at Nemea. Perseus is depicted as being borne to Seriphos, carrying the head of Medusa to Polydectes. However, I have no desire to discuss the story of Medusa in this Attic description. Moreover, among the paintings present is a depiction of a boy carrying water jars and the wrestler painted by Timainetos; this figure is Mousaios. Personally, I have read certain epic lines wherein Mousaios is said to fly through the air by a gift from Boreas. Yet it seems to me that these poems were composed by Onomakritos, and there is nothing truly authentic by Mousaios except the hymn to Demeter written for the Lykomidai.