Passage 10.12.8
τὴν δὲ ἐπὶ ταύτῃ χρησμοὺς κατὰ ταὐτὰ εἰποῦσαν ἐκ Κύμης τῆς ἐν Ὀπικοῖς εἶναι, καλεῖσθαι δὲ αὐτὴν Δημὼ συνέγραψεν Ὑπέροχος ἀνὴρ Κυμαῖος. χρησμὸν δὲ οἱ Κυμαῖοι τῆς γυναικὸς ταύτης ἐς οὐδένα εἶχον ἐπιδείξασθαι, λίθου δὲ ὑδρίαν ἐν Ἀπόλλωνος ἱερῷ δεικνύουσιν οὐ μεγάλην, τῆς Σιβύλλης ἐνταῦθα κεῖσθαι φάμενοι τὰ ὀστᾶ.
Concerning another Sibyl, named Demo, Hyperochus, a man of Cumae, wrote that she came from Cumae in the Opican land, and likewise uttered oracles. The people of Cumae, however, had no oracle uttered by this woman to show; but they show in the sanctuary of Apollo a small stone water-jar, saying that the bones of this Sibyl rest there.