Passage 8.15.3
καὶ ἐπίθημα ἐπʼ αὐτῷ περιφερές ἐστιν, ἔχον ἐντὸς Δήμητρος πρόσωπον Κιδαρίας· τοῦτο ὁ ἱερεὺς περιθέμενος τὸ πρόσωπον ἐν τῇ μείζονι καλουμένῃ τελετῇ ῥάβδοις κατὰ λόγον δή τινα τοὺς ὑποχθονίους παίει. Φενεατῶν δέ ἐστι λόγος, καὶ πρὶν ἢ Ναὸν ἀφικέσθαι γὰρ καὶ ἐνταῦθα Δήμητρα πλανωμένην· ὅσοι δὲ Φενεατῶν οἴκῳ τε καὶ ξενίοις ἐδέξαντο αὐτήν, τούτοις τὰ ὄσπρια ἡ θεὸς τὰ ἄλλα, κύαμον δὲ οὐκ ἔδωκέ σφισι.
Upon it is a circular covering, which contains within it the mask of Demeter called Kidaria. In the greater rite, as it is called, the priest places this mask upon himself and strikes the subterranean deities with rods, according, it seems, to a certain ritual tradition. According to a legend of the Pheneatians, Demeter also wandered to this place before she arrived at Naos; those among the Pheneatians who received the goddess into their homes and as a guest were given by her all the pulses except the bean.