The hammock of pure silk and the cap which later closes it are evidently only scaffolding intended to support the masonry of sand and to give it a regular curve. One might compare them to the constructions used by builders when making an arch or vault. The work being completed, the silken support disappears, partly lost in the masonry, and partly destroyed by contact with rough earth, and no trace remains of the ingenious method employed to put together a construction perfectly regular, yet made of a material so little coherent as is sand. The spherical cap which closes the original basket is a separate work, adjusted to the main body of the cocoon. However well the two pieces are fitted and soldered, the solidity is not such as the larva would obtain had it built the whole dwelling continuously. Thus, on the circumference of the cover there is a circular line less capable of resistance, but this is not a fault of construction. On the contrary it is a fresh perfection. The insect would experience grave difficulty in issuing from its strong box, so thick are the walls, did not the line of junction, weaker than the rest, apparently save much effort, as it is usually along this line that the cover is detached when the perfect Bembex emerges. I have called the cocoon a strong box. It is indeed a solid article, both from its shape and the nature of its materials. Landslips or falling sand cannot alter its form, since the strongest pressure of one’s fingers cannot always crush it. Thus it matters little to the larva if the ceiling of its burrow, dug in loose soil, should sooner or later fall in, and it need not fear, even should a passing foot press down the thin covering of sand; it runs no risks when once enclosed in its stout shelter. Nor does damp endanger it. I have immersed Bembex cocoons for a fortnight in water without finding any trace of damp inside them. Ah! why cannot we have such waterproof for our dwellings? To sum up: the cocoon, of graceful oval shape, appears rather the product of patient art than the work of a grub. For any one not behind the scenes, the cocoons which I saw in process of construction with the sand from my inkstand might well have been precious articles of some unknown industry—great beads starred with golden dots on a ground of lapis lazuli, destined for the necklace of some Polynesian belle. XIX THE RETURN TO THE NEST