ἡ κέρκος τῇ ἀλώπεκι μαρτυρεῖ → you can tell a fox by its tail, small traits give the clue to the character of a person
prae-rĭgĭdus: a, um, adj.,I very stiff, very rigid (late Lat.): mens, Auct. Quint. Decl. 17, 7.