Passage 2.35.5
Χθονία δʼ οὖν ἡ θεός τε αὐτὴ καλεῖται καὶ Χθόνια ἑορτὴν κατὰ ἔτος ἄγουσιν ὥρᾳ θέρους, ἄγουσι δὲ οὕτως. ἡγοῦνται μὲν αὐτοῖς τῆς πομπῆς οἵ τε ἱερεῖς τῶν θεῶν καὶ ὅσοι τὰς ἐπετείους ἀρχὰς ἔχουσιν, ἕπονται δὲ καὶ γυναῖκες καὶ ἄνδρες. τοῖς δὲ καὶ παισὶν ἔτι οὖσι καθέστηκεν ἤδη τὴν θεὸν τιμᾶν τῇ πομπῇ· οὗτοι λευκὴν ἐσθῆτα καὶ ἐπὶ ταῖς κεφαλαῖς ἔχουσι στεφάνους. πλέκονται δὲ οἱ στέφανοί σφισιν ἐκ τοῦ ἄνθους ὃ καλοῦσιν οἱ ταύτῃ κοσμοσάνδαλον, ὑάκινθον ἐμοὶ δοκεῖν ὄντα καὶ μεγέθει καὶ χρόᾳ· ἔπεστι δέ οἱ καὶ τὰ ἐπὶ τῷ θρήνῳ γράμματα.
The goddess herself is called Chthonia, and each year they celebrate a festival called the Chthonia during summertime, which they perform in this manner. Leading their procession are the priests of the gods and those who hold annual offices, followed by men and women. Even the children take part in honoring the goddess by joining the procession; they wear white garments and wreaths on their heads. Their wreaths are woven from the flower that the locals call kosmosandalon, which, in my view, resembles a hyacinth both in size and color; it even bears the same markings found in the lament associated with the hyacinth.