οἱ κατὰ χθονός
From LSJ
τὰ πρὸ Εὐκλείδου ἐξετάζειν → investigate what happened before the flood, investigate what happened in the distant past, investigate what happened before Euclid, investigate what happened before the year of Euclid
Greek > English (Woodhouse)
the dead, the Lower World, the shades, the underworld, those below, those in the underworld