Davus sum, non dipus (I am a plain, simple fellow, and no
solver of riddles, like dipus). The words are from Terence's
Andria, i. 2, 23.
Non te credas Davum ludere.
Don't imagine you are deluding Davus. “Do you see any white in my
eye?” I am not such a fool as you think me to be.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894