Passage 10.33.10
ὡς δὲ ὁ πατὴρ ἦλθε τοῦ παιδός, τὸν δράκοντα ἐπιβουλεῦσαι τῷ παιδὶ ἐλπίζων ἀφίησι τὸ ἀκόντιον, καὶ ἐκεῖνόν τε καὶ ὁμοῦ τῷ δράκοντι τὸν παῖδα ἀπέκτεινε· διδαχθεὶς δὲ ὑπὸ τῶν ποιμαινόντων ὡς εὐεργέτην καὶ φύλακα τοῦ παιδὸς ἀπεκτονὼς εἴη, πυρὰν τῷ δράκοντι καὶ τῷ παιδὶ ἐποίησεν ἐν κοινῷ. τό τε δὴ χωρίον ἐοικέναι καὶ ἐς τόδε καιομένῃ πυρᾷ φασι καὶ ἀπὸ τοῦ δράκοντος ἐκείνου τὴν πόλιν ἐθέλουσιν Ὀφιτείαν ὀνομασθῆναι.
When the child's father arrived, thinking that the serpent was intending harm to his son, he hurled his spear, and slew both the serpent and his child along with it. Afterwards, having been informed by the herdsmen that he had killed the creature which had acted as guardian and benefactor to his child, he constructed a common funeral pyre for both the serpent and the boy. Even to this day, they say, the spot resembles a burning pyre, and they wish to believe that it was from this very serpent that the city received its name, Ophiteia.