sing and falling, protruding and retreating like a piston-rod,
but it is impossible to observe the precise nature of their action,
bathed as they are in the opaque blob of foam.

The end of the abdomen, continually palpitating, rapidly closing and
opening its valves, oscillates right and left like a pendulum. From each
of these oscillations results a layer of eggs in the interior, and a
transversal crevice on the exterior. As it advances in the arc
described, suddenly, and at frequent intervals, it plunges deeper into
the foam, as though burying something at the bottom of the frothy mass.
Each time it does so an egg is doubtless deposited; but the operation is
so rapid, and takes place under conditions so unfavourable for
observation, that I have never once been enabled to see the oviduct at
work. I can only judge of the advent of the eggs by the movements of the
end of the abdomen, which is immersed more deeply with a sudden plunging
movement.

At the same time the viscous composition is emitted in intermittent
waves, and is beaten into a foam by the terminal valves. The foam thus
obtained spreads itself over the sides and at the base of the layer of
eggs, and projects through the meshes of the wire gauze as a result of
the pressure of the abdomen. Thus the spongy envelope is progressively
created as the ovaries are gradually emptied.

I imagine, although I cannot speak as the result of direct observation,
that for the central core, where the eggs are surrounded by a material
more homogeneous than that of the outer shell, the Mantis must employ
her secretion as it emerges, without beating it into a foam. The layer
of eggs once deposited, the two valves would produce the foam required
to envelop the eggs. It is extremely difficult, however, to guess what
occurs beneath the veil of foam-like secretion.

In a recent nest the zone of issue is surrounded by a layer of finely
porous matter, of a pure matt, almost chalky white, which contrasts
distinctly with the remainder of the nest, which is of a dirty white. It
resembles the icing composition made by confectioners with whipped white
of egg, sugar, and starch, for the ornamentation of cakes.

This snowy border is easily crumbled and easily detached. When it
disappears the zone of issue is clearly defined, with its double series
of leaves with free edges. Exposure to the weather, wind, and rain
result in its disappearance, fragment by fragment, so that old nests
preser