In twenty-four hours they had sunk themselves through the entire thickness of the earth--a matter of some four inches.

But for obstacle at the bottom they would have sunk even further.
On the way they have probably encountered the rootlets of my little plantation.

Did they halt in order to take a little nourishment by implanting their proboscis?
This is hardly probable, for a few rootlets were pressed against the bottom of the glass, but none of my prisoners were feeding.

Perhaps the shock of reversing the pot detached them.
It is obvious that underground there is no other nourishment for them than the sap of roots.

Adult or larva, the Cigale is a strict vegetarian.