Besides, what good would those short-sighted lenses be in the absence of light, in black darkness?
It is equally useless to think of the sense of smell.

Has the Processional any olfactory powers or has he not?
I do not know.

Without giving a positive answer to the question, I can at least declare that his sense of smell is exceedingly dull and in no way suited to help him find his way.

This is proved, in my experiments, by a number of hungry caterpillars that, after a long fast, pass close beside a pine-branch without betraying any eagerness of showing a sign of stopping.

It is the sense of touch that tells them where they are.