Passage 5.9.6
πιεσθέντες δὲ ὑπὸ Ἀρκάδων πολέμῳ μοῖράν τε ἀπέβαλον τῆς γῆς καὶ ὅσοι τῶν δήμων ἦσαν ἐν τῇ ἀποτμηθείσῃ χώρᾳ, καὶ οὕτως ἐς ὀκτώ τε ἀριθμὸν φυλῶν ἐπὶ τῆς τετάρτης συνεστάλησαν Ὀλυμπιάδος καὶ ἑκατοστῆς καὶ Ἑλλανοδίκαι σφίσιν ἴσοι ταῖς φυλαῖς ᾑρέθησαν. ὀγδόῃ δὲ ἐπὶ ταῖς ἑκατὸν Ὀλυμπιάδι ἐπανῆλθον αὖθις ἐς ἀνδρῶν δέκα ἀριθμόν, καὶ ἤδη τὸ ἀπὸ τούτου διαμεμένηκεν ἐς ἡμᾶς.
Having been pressed in war by the Arcadians, they lost a portion of their territory, together with all the districts that were located within the severed region. Thus, in the hundred and fourth Olympiad, they were reduced to eight tribes, and the number of Hellanodikai appointed was equal to the tribes. In the hundred and eighth Olympiad, however, they again returned to the number of ten men, and from then on this number has endured down to our own time.