The end of the abdomen, ever throbbing, quickly opening and closing its valves, swings from right to left and left to right like a pendulum. The result of each swing is a layer of eggs inside and a transversal furrow outside. As the abdomen advances in the arc described, suddenly and at very close intervals it dips deeper into the foam, as though it were pushing something to the bottom of the frothy mass. Each time, no doubt, an egg is laid; but things happen so fast and under conditions so unfavourable to observation that I never once succeed in seeing the ovipositor at work. I can judge of the arrival of the eggs only by the movements of the tip of the abdomen, which suddenly drives down and immerses itself more deeply. At the same time, the viscous stuff is poured forth in intermittent waves and whipped and turned into foam by the two terminal valves. The froth obtained spreads over the sides of the layer of eggs and at the base, where I see it, pressed back by the abdomen, projecting through the meshes of the gauze. Thus the spongy covering is gradually brought into being as the ovaries are emptied. I imagine, without being able to rely on direct observation, that for the central kernel, where the eggs are contained in a more homogeneous material than the rind, the Mantis employs her product as it is, without beating it up and making it foam. When the eggs are deposited, the two valves would produce foam to cover them. Once again, however, all this is very difficult to follow under the veil of the bubbling mass. In a new nest, the exit-zone is coated with a layer of fine porous matter, of a pure, dull, almost chalky white, which contrasts with the dirty white of the remainder of the nest. It is like the composition which confectioners make out of whipped white of egg, sugar and starch, with which to ornament their cakes. This snowy covering is very easily crumbled and removed. When it is gone, the exit-zone is clearly defined, with its two rows of plates with free edges. The weather, the wind and the rain sooner or later remove it in strips and flakes; and therefore the old nests retain no traces of it. At the first inspection, one might be tempted to look upon this snowy matter as a different substance from the remainder of the nest. But can it be that the Mantis really employs two different products? By no means. Anatomy, to begin with, assures us of the unity of the materials. The organ that secretes the substance of the nest consists of twisted cylindrical tubes, divided into two sections of twenty each. All are filled with a colourless, viscous fluid, exactly similar in appearance wherever we look. There is nowhere any sign of a product with a chalky colouring.