Passage 9.40.1
τὸ δὲ μαντεῖον οἱ Βοιωτοὶ τοῦτο οὐ πεπυσμένοι πρότερον ἐπʼ αἰτίᾳ τοιᾷδε ἔγνωσαν. θεωροὺς ἀφʼ ἑκάστης πόλεως ἄνδρας ἀποστέλλουσιν ἐς Δελφούς· οὐ γὰρ δή σφισιν ἔτος δεύτερον ὗεν ὁ θεός. τούτοις αἰτοῦσιν ἐπανόρθωμα τοῦ αὐχμοῦ προσέταξεν ἡ Πυθία παρὰ Τροφώνιον ἐς Λεβάδειαν ἐλθοῦσιν εὕρασθαι παρὰ ἐκείνου τὸ ἴαμα.
The Boeotians, who were previously unfamiliar with this oracle, came to know of it under the following circumstances. They dispatched delegates from each city to Delphi, since the god had granted them no rain for two consecutive years. When they requested relief from this drought, the Pythian priestess instructed them to go to Lebadeia and seek from Trophonios the remedy there.