The large central nest is the cocoon of a moth belonging to the genus Oiketicus, or Housebuilder. There are many species of Housebuilder moths, and all are remarkable for the fact that the larva never exhibits itself, but builds a dwelling in which it conceals itself, just as does the well-known caddis-worm. Indeed the nests of several Oiketici look exactly as if the dwelling of a caddis-worm had been greatly enlarged and hung up in a tree. [Illustration: Nests of Oiketicus, &c.] The nest of this species, however, differs from that of the common Oiketicus by being covered with a coating of greyish silk. If we cut open the silk, we find a great number of little sticks and leaf-stems crossed on each other, and showing their ends through the silken cover. Within these defences there is a layer of leaves cut into small pieces, and lastly comes the cell inhabited by the caterpillar. It is lined with a silken web similar in character to that on the outside, but finer, stronger, and whiter The caterpillar is therefore defended by four distinct barriers. First comes the strong silken web which lines the cell, and next is the layer of leaf fragments. Outside them comes the _chevaux de frise_ of crossed sticks, and lastly we have the grey silken web. This outer wrapper has no connection with the interior of the cell, and is only lightly attached to the ends of the cross sticks. Within this curious dwelling the caterpillar conceals the whole of its body, clinging to the branch or leaf by its feet, and if alarmed drawing itself up so that the mouth of the cocoon is pressed tightly against the branch, and effectually conceals even the feet which hold it. The other figure on the right hand represents the dwelling of another Housebuilder caterpillar. It looks very much as if it were made of drab cloth. The most remarkable point about it is the lower end. When the insect is within the dwelling the extremity has a spiral twist, but when the moth has escaped the spiral form is destroyed, and it appears as represented in the illustration. The female Oiketicus never attains the winged state nor leaves her house, but lives and dies in it, almost unchanged in shape. In fact, the adult female is even more undeveloped in appearance than the caterpillar, and looks like a large, fat, unwieldy grub, covered with down. The male, on the contrary, is a tolerably active moth, with sharply-pointed wings and beautiful feathered antennæ. Another kind of Housebuilder's residence is shown in the lower left-hand figure, enveloped and almost concealed by leaves. The remaining figures represent the dwellings of two unknown insects, both from Australia. The upper left-hand nest is made wonderfully like that of the weaver-bird, being composed of fibres like cow-hairs woven loosely together. It is brown outside and white in the interior.