E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Cortina.
The skin of the serpent Pytho, which covered the tripod of
the Pythoness when she delivered her oracles. Tripodas cortina tegit (Prudentius: Apophthegmata, 506); also the tripod itself, or the place where the oracle was delivered. (Virgil: Ænid, vi. 345.) Neque te Phbi cortina fefellit.