This species is allied to the Weaver Birds, some of which have already been described, and makes a nest which is no whit inferior to those which have already been mentioned. The Sociable Weaver Bird is a native of Southern Africa, and in some places is very plentiful, its presence depending much upon the trees which clothe the country. It is not a large bird, measuring about five inches in length, and is very inconspicuous, its colour being pale buff, mottled on the back with deep brown. The chief interest about the species is concentrated in its nest, which is a wonderful specimen of bird architecture, and attracts the attention of the most unobservant traveller. Few persons expect to see in a tree a nest which is large enough to shelter five or six men; and yet that is often the case with the nest of the Sociable Weaver Bird. Of course so enormous a structure is not the work of a single pair, but, like the dam of the beaver, is made by the united efforts of the community. How it is made will now be described.

Large as is the domicile, and capable at last of containing a vast number of parents and young, it is originally the work of a single pair, and attains its enormous dimensions by the labours of those birds which choose to associate in common. The first task of this Weaver Bird is to procure a large quantity of the herb which really seems as if made expressly for the purpose. This is a grass with a very large, very tough, and very wiry blade, which is known to the colonists as Booschmannie grass, probably because it grows plentifully in that part of Southern Africa where the Bushmen, or Bosjesmans live.

They carry this grass to some suitable tree, which is usually a species of acacia, called by the Dutch colonists Kameel-dorn (Acacia giraffa), because the giraffe, which the Dutch persist in calling a kameel or camel, is fond of grazing on the leaves. This is a most appropriate tree for the purpose, as the wood is extremely hard and tough, and the branches are therefore able to bear the great weight of the nests. This tree is used in Southern Africa for many purposes wherein hardness and endurance are required, such as the axle-trees of the wooden waggons, which have to withstand such rough usage, the upright timbers of houses, and the handles of tools, especially those which are intended for agricultural purposes.

The birds then hang the Booschmannie grass over a suitable

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branch, and by means of weaving and plaiting it, they form a roof of some little size. Under this roof are placed a quantity of nests, increasing in number with each successive brood. The nests are set closely together, so that at last they look like a mass of grass pierced with numerous holes, and it is really wonderful that the birds should be able to find their way to their own particular homes. To human eyes, the nests are as much alike as the houses in a modern street, before the blinds, the flowers, and other additions have communicated an individuality to each dwelling; but, notwithstanding this similarity, the inmates glide in and out without any hesitation.

Although the same nest-mass is occupied for several successive seasons, the birds refuse to build in the same nests a second time, preferring to make a fresh domicile for each new brood. In consequence of this custom, when the birds have entirely filled the roofs with their nests, they do not desert it, but enlarge the roof, and build a second row of nests, just like the combs of a wasp's or hornet's habitation.

Layer after layer is thus added, until the mass becomes of so enormous a size that travellers have mistaken these nests for the houses of human beings, and been grievously disappointed when they came near enough to detect their real character. There is a story of a Hottentot and a lion, which will give an idea of the dimensions of these nests. A Hottentot, who was engaged in some task, was suddenly surprised by a lion, and instinctively made for the nearest tree, which happened to be a kameel-dorn. Up the tree he sprang, and finding one of the branches occupied by the nest of the Sociable Weaver Bird, he took refuge behind. the grassy mass, and was thus concealed from the pursuer.

The lion, in the meantime, arrived at the foot of the tree, but could not see his intended prey. The unlucky Hottentot, however, peeped over the nest in order to see whether the coast was clear, and was spied by the lion, who made a dash at the tree. The man shrank back behind the nest, but his imprudent movement brought its own punishment.

Knowing that the ascent of the tree was impossible, and at the same time unwilling to leave its prey, the lion sat down at the foot of the tree, and kept watch upon the man. Hour after hour the lion mounted guard over its prisoner, until thirst overpowered hunger, and the animal was forced reluctantly to quit

its post and seek for water. The man then scrambled down the tree, and made the best of his way homewards, little the worse for his imprisonment except the fright, and a skin scorched by long exposure to the sun. The artist has introduced this little episode into the illustration, because it enables the reader to judge of the enormous size of the nest.

Season after season the Weaver Birds continue to add their nests, until at last the branch is unable to endure the weight, and comes crashing to the ground. This accident does not often occur during the breeding months, but mostly takes place during the rainy season, the dried grass absorbing so much moisture, that the weight becomes too great for the branch to bear.

The nest group which is shown in the illustration is of medium size, as can be ascertained by its shape. In its early state, the nest-mass is comparatively long and narrow, spreading out by degrees as the number of nests increases, so that at last it is as wide and as shallow as an extended umbrella. The dimensions of some of these structures may be gathered from the fact, that Le Vaillant counted in one unfinished edifice, beside the deserted nests of previous seasons, no less than three hundred and twenty nests, each of which was occupied by a pair of birds engaged in bringing up a brood of young, four or five in number.

Those who are acquainted with Borneo and the customs of its inhabitants, cannot fail to perceive the analogy between these social nests of the Weaver Bird and the "long houses" of the Dyaks, each of which houses is in fact one entire village, sheltering a whole community under a single roof.

The Weaver Birds have but few enemies. First, there are the snakes, which are such determined robbers of nests, swallowing both eggs and young; and then there are the monkeys, which are capable of sad depredations whenever they can find an opportunity. Monkeys are extremely fond of eggs, and there is scarcely a better bribe to a monkey, ape, or baboon, than a fresh raw egg. The bird which laid it is almost as great a dainty, and a monkey seems to be in the height of enjoyment if a newly-killed bird be put into its paws. It always begins by eating the brain, and then tears the carcase to pieces with great deliberation. A mouse is quite as much appreciated as a bird, provided

that it has been recently killed, and that the blood has not congealed.

However, the structure of the nest forms an insurmountable barrier to the snake, and the monkey can only reach a few of the cells which are near the edge. The worst enemies are certain little parrakeets, which are delighted to be able to procure nests without the trouble of building them, and which are apt to take possession of the cells and oust the rightful owners.

CHAPTER XXIII.

SOCIAL INSECTS.

Arrangement of groups-Nests of POLYBIA-Curious method of enlargementStructure of the nests-How concealed-Various modes of attachment-A curious specimen-The HIVE BEE, and its claims to notice-General history of the hive-Form of the cells-The royal cell, its structure and use- -Uses of the ordinary cells-Structure of the Bee-cell-Economy of space-How producedTheories of different mathematicians-Measurement of angles-A logarithmic table corrected by the bee-cell-The "lozenge," a key to the cell-How to form it-Beautiful mathematic proportions of the lozenge-Method of making the cell or a model-Conjectured analogy between the cell and certain crystalsEffect of the cell upon honey-The HORNET and its nest-Its favourite localities --Difficulties of taking a hornet's nest-Habits of the insect-Mr. Stone's method of taking the nest-The SYNŒCA and its habitation-Beautiful nests in the British Museum-Description of the insect-Nest of the EUCHEIRA-Its external form-Curious discovery in dissection-A suspended colony-Conjectures respecting the structure-Nest from the Oxford Museum-Remarkable form of its doors, and material of which it is made-The SMALL ERMINE MOTH-and its ravages-Its large social habitation-General habits of the larva-why the sparrow does not eat them-The GOLD-TAILED MOTH, and its beautiful social nest-Description of a specimen from Wiltshire-Illustration of the theory of heat-The BROWN-TAILED MOTH and its nest-Social habitations of the PEACH and SMALL TORTOISESHELL BUTTERFLIES.

AFTER the Social Birds come the SOCIAL INSECTS, to which the following chapter is dedicated.

The reader will probably have noticed that several insects, especially those of the hymenopterous order, seem to have been omitted in previous chapters, although they might fairly claim admission into the ranks of Builders, Pensiles, Burrowers, and Subaquatics. The fact is, that some of them unite the characteristics of several groups, and may therefore be placed in either of them. For example, the South American wasp, which makes the nest called popularly the "Dutchman's pipe," may be ranked either as a builder, a pensile, or a social insect. In such cases, therefore, I have endeavoured to select that characteristic which seems to be marked most strongly, and have arranged the insects accordingly.