So long as their lips do not chance to light upon the pasture-land, not one of them settles there, though he be ravenous.

They do not hasten to food which they have scented from afar; they stop at a branch which they encounter on their way.
Apart from sight and smell, what remains to guide them in returning to the nest?
The ribbon spun on the road.

In the Cretan labyrinth, Theseus would have been lost but for the clue of thread with which Ariadne supplied him.

The spreading maze of the pine-needles is, especially at night, as inextricable a labyrinth as that constructed for Minos.

The Processionary finds his way through it, without the possibility of a mistake, by the aid of his bit of silk.