The most remarkable circumstance in the architecture of this species of vespiary is, that it is not horizontal, like those formerly described, but nearly vertical. The reason appears to be, that if it had been horizontal, the cells must have been frequently filled with rain; whereas, in the position in which it is placed, the rain runs off without lodging. It is, besides, invariably placed so as to face the north or the east, and consequently is less exposed to rains, which most frequently come with southerly or westerly winds. It is another remarkable peculiarity, that, unlike the nests of other wasps, it is covered with a shining coat of varnish, to prevent moisture from soaking into the texture of the wasp's paper. The laying on this varnish, indeed, forms a considerable portion of the labour of the colony, and individuals may be seen employed for hours together spreading it on with their tongues. [Illustration: Comb of Polistes.] [There is a genus of foreign hymenoptera, called _Polistes_, which is remarkable for the building powers possessed by its members. The accompanying illustration is taken from a nest in the British Museum, and is given of the natural size. The cells are not hexagonal, like those of the _Epipone_, but are roundish in form. Those in the centre assume a roughly hexagonal form by pressure, but those which form the circumference of the cell-group are nearly round, especially on their outer sides. The cells are not of uniform width, but are narrower at the base than at the mouth, thus causing the group to assume the form which is seen in the illustration. This curious group of cells was brought from Bareilly, in the East Indies, and in the same collection there are several other specimens, varying considerably both in shape and size.] Few circumstances are more striking, with regard to insects, as Kirby and Spence justly remark, than the great and incessant labour which maternal affection for their progeny leads them to undergo. Some of these exertions are so disproportionate to the size of the insect, that nothing short of ocular conviction could attribute them to such an agent. A wild bee, or a wasp, for instance, as we have seen, will dig a hole in a hard bank of earth some inches deep, and five or six times its own size, labouring unremittingly at this arduous task for several days in succession, and scarcely allowing itself a moment for eating or repose. It will then occupy as much time in searching for a store of food; and no sooner is this finished, than it will set about repeating the process, and, before it dies, will have completed five or six similar cells, or even more.