While the others follow passively in a close file, he, the captain, tosses himself about and with an abrupt movement flings the front of his body hither and thither.

As he marches ahead he seems to be seeking his way.
Does he in point of fact explore the country?
Does he choose the most practicable places?
Or are his hesitations merely the result of the absence of a guiding thread on ground that has not yet been covered?
His subordinates follow very placidly, reassured by the cord which they hold between their legs; he, deprived of that support, is uneasy.
Why cannot I read what passes under his black, shiny skull, so like a drop of tar to look at?
To judge by actions, there is here a modicum of discernment which is able, after experimenting, to recognize excessive roughnesses, over-slippery surfaces, dusty places that offer no resistance and, above all, the threads left by other excursionists.
This is all or nearly all that my long acquaintance with the Processionaries has taught me as to their mentality.

Poor brains, indeed; poor creatures, whose commonwealth has its safety hanging upon a thread! The processions vary greatly in length.

The finest that I have seen manoeuvring on the ground measured twelve or thirteen yards and numbered about three hundred caterpillars, drawn up with absolute precision in a wavy line.

But, if there were only two in a row the order would still be perfect: the second touches and follows the first.
By February I have processions of all lengths in the greenhouse.