Passage 8.38.3
ταῖς Νύμφαις δὲ ὀνόματα, ὑφʼ ὧν τὸν Δία τραφῆναι λέγουσι, τίθενται Θεισόαν καὶ Νέδαν καὶ Ἁγνώ· καὶ ἀπὸ μὲν τῆς Θεισόας πόλις ᾠκεῖτο ἐν τῇ Παρρασίᾳ, τὰ δὲ ἐπʼ ἐμοῦ μοίρας τῆς Μεγαλοπολίτιδός ἐστιν ἡ Θεισόα κώμη· τῆς Νέδας δὲ ὁ ποταμὸς τὸ ὄνομα ἔσχηκε· τῆς δὲ Ἁγνοῦς, ἣ ἐν τῷ ὄρει τῷ Λυκαίῳ πηγὴ κατὰ τὰ αὐτὰ ποταμῷ τῷ Ἴστρῳ πέφυκεν ἴσον παρέχεσθαι τὸ ὕδωρ ἐν χειμῶνι ὁμοίως καὶ ἐν ὥρᾳ θέρους.
The names given to the Nymphs, who are said to have nurtured Zeus, are Thesoa, Neda, and Hagno. From Thesoa a city was founded in Parrhasia; in my day Thesoa is a village belonging to the territory of Megalopolis. From Neda the river has taken its name; and from Hagno comes a spring on Mount Lycaeus whose waters flow like the river Ister, maintaining the same volume in winter as in the summer season.