I will call this zone the zone of issue, as it is only along this bell that the young can escape, being set free by those that have preceded them.
In all other directions the cradle of this numerous family presents an unbroken wall.

The two lateral zones, which occupy the greater part of the demi-ellipsoid, have a perfect continuity of surface.

The little Mantes, which are very feeble when first hatched, could not possibly make their way through the tenacious substance of the walls.

On the interior of these walls are a number of fine transverse furrows, signs of the various layers in which the mass of eggs is disposed.
Let us cut the nest in half transversely.

We shall then see that the mass of eggs constitutes an elongated core, of very firm consistency, surrounded as to the bottom and sides by a thick porous rind, like solidified foam.