Passage 5.17.5
λάρναξ δὲ κέδρου μὲν πεποίηται, ζῴδια δὲ ἐλέφαντος ἐπʼ αὐτῆς, τὰ δὲ χρυσοῦ, τὰ δὲ καὶ ἐξ αὐτῆς ἐστιν εἰργασμένα τῆς κέδρου· ἐς ταύτην τὴν λάρνακα Κύψελον τὸν Κορίνθου τυραννήσαντα ἀπέκρυψεν ἡ μήτηρ, ἡνίκα τεχθέντα ἀνευρεῖν αὐτὸν σπουδὴν ἐποιοῦντο οἱ Βακχίδαι. τῆς μὲν δὴ σωτηρίας ἕνεκα τοῦ Κυψέλου τὸ ἀπʼ αὐτοῦ γένος οἱ ὀνομαζόμενοι Κυψελίδαι τὴν λάρνακα ἐς Ὀλυμπίαν ἀνέθεσαν, τὰς δὲ λάρνακας οἱ τότε ἐκάλουν Κορίνθιοι κυψέλας· ἀπὸ τούτου δὲ καὶ ὄνομα Κύψελον τῷ παιδὶ θέσθαι λέγουσι.
The chest is made of cedar wood; upon it are figures carved from ivory, others of gold, while some are fashioned out of the cedar itself. Into this chest the mother of Cypselus hid him when the Bacchiadae, immediately after his birth, were earnestly seeking to find him. Afterwards, because of this rescue of Cypselus, his descendants, called Cypselidae, dedicated the chest at Olympia. In those days, the Corinthians called such chests "cypselae," and thus it is said that the boy himself was also named Cypselus.