Passage 10.4.3
τὸ ἕτερον δὲ οὐκ ἐδυνήθην συμβαλέσθαι πρότερον, ἐφʼ ὅτῳ καλλίχορον τὸν Πανοπέα εἴρηκε, πρὶν ἢ ἐδιδάχθην ὑπὸ τῶν παρʼ Ἀθηναίοις καλουμένων Θυιάδων. αἱ δὲ Θυιάδες γυναῖκες μέν εἰσιν Ἀττικαί, φοιτῶσαι δὲ ἐς τὸν Παρνασσὸν παρὰ ἔτος αὐταί τε καὶ αἱ γυναῖκες Δελφῶν ἄγουσιν ὄργια Διονύσῳ. ταύταις ταῖς Θυιάσι κατὰ τὴν ἐξ Ἀθηνῶν ὁδὸν καὶ ἀλλαχοῦ χοροὺς ἱστάναι καὶ παρὰ τοῖς Πανοπεῦσι καθέστηκε· καὶ ἡ ἐπίκλησις ἡ ἐς τὸν Πανοπέα Ὁμήρου ὑποσημαίνειν τῶν Θυιάδων δοκεῖ τὸν χορόν.
The second point I was previously unable to interpret was why Homer called Panopeus "beautiful-for-dancing" (Kallichoros), until I was instructed by those women whom the Athenians call the Thyiades. These Thyiades are women from Attica who travel every second year to Parnassus, and together with the Delphic women, celebrate the rituals in honor of Dionysus. It is customary for these Thyiades, as they journey from Athens, to perform dances along their route in various places, among them the city of Panopeus. And indeed, Homer’s epithet concerning Panopeus seems to allude to this very dance of the Thyiades.