Passage 9.10.5
ἀνωτέρω δὲ τοῦ Ἰσμηνίου τὴν κρήνην ἴδοις ἄν, ἥντινα Ἄρεώς φασιν ἱερὰν εἶναι καὶ δράκοντα ὑπὸ τοῦ Ἄρεως ἐπιτετάχθαι φύλακα τῇ πηγῇ. πρὸς ταύτῃ τῇ κρήνῃ τάφος ἐστὶ Καάνθου· Μελίας δὲ ἀδελφὸν καὶ Ὠκεανοῦ παῖδα εἶναι Κάανθον λέγουσι, σταλῆναι δὲ ὑπὸ τοῦ πατρὸς ζητήσοντα ἡρπασμένην τὴν ἀδελφήν. ὡς δὲ Ἀπόλλωνα εὑρὼν ἔχοντα τὴν Μελίαν οὐκ ἐδύνατο ἀφελέσθαι, πῦρ ἐτόλμησεν ἐς τὸ τέμενος ἐνεῖναι τοῦ Ἀπόλλωνος τοῦτο ὃ νῦν καλοῦσιν Ἰσμήνιον· καὶ αὐτὸν ὁ θεός, καθά φασιν οἱ Θηβαῖοι, τοξεύει.
Above the Ismenion, one may see the spring which is said to be sacred to Ares, and a dragon, it is believed, was appointed by Ares himself as guardian of this spring. Near this spring is the tomb of Caanthus. They relate that Caanthus was the brother of Melia and the son of Oceanus, and that he was sent by his father to search for his sister after she had been abducted. But when he found Apollo holding Melia and could not take her away, he dared to set fire to the sanctuary of Apollo, the one that is now called the Ismenion. The god himself, according to the Thebans' story, shot and killed Caanthus with an arrow.