and Mr. Rennie; mining bees of the genus Andrena, who dig deep burrows in clay, placing at the bottom honey and pollen for the young when hatched; some of the species, we are told, are treated much as the wives of savages are treated, for all the work is done by the females, while the males do nothing but amuse themselves, circling about the nests in graceful undulations.' Others belonging to the genera Pompilus, Mellinus, Oxybelus Philanthus, and Bombus; some preferring spiders as food, others beetles, others the hive-bees. Of the hive-bee-eating British hymenoptera, the boldest, we are told, is the Philanthus triangulum, for 'it provisions its nest with the common hive-bee, seizing the luckless honey-makers and carrying them off to its nest.' But of all hymenopterous insects none perhaps surpass the common wasp as a builder of a subterranean abode. Although every one is acquainted with the general appearance and structure of a wasp's nest, few have observed it in the course of manufacture :

In the early days of spring, a wasp issues from the place in which it has passed the winter and anxiously surveys the country. She docs not fly fast nor high, but passes slowly and carefully along, examining every earth-bank and entering every crevice to which she comes. At last she finds a burrow made by a field-mouse, or perhaps strikes upon the deserted tunnel of some large burrowing insect, enters it, stays a long while within, comes out again and fusses about outside, enters again, and seems to make up her mind. In fact, she is house-hunting, and all her movements are very like those of a careful matron selecting a new home. Having thus settled upon a convenient spot, she proceeds to form a chamber, at some depth from the surface, breaking away the soil, and carrying it out piece by piece. When she has thus fashioned the chamber to her mind-for she has a mind-she flies off again, and makes her way to an old wooden fence which has stood for many years, and which although not rotten, is perfectly seasoned. On this she settles, and after running up and down for a little time, she fixes upon some spot and begins to gnaw away the fibres, working with all her might. . . . At last she has gathered a little bundle of fibres, which she gnaws and works about until she reduces them to a kind of pulp, and then flies back to the burrow.'

...

The bundles of ligneous fibres thus detached, to quote the language of the author of Insect Architecture,' are moistened before being used with a glutinous liquid which causes them to adhere together, and are then kneaded into a sort of paste, or papier maché. Having prepared some of this material, the mother wasp begins first to line with it the roof of her chamber, for wasps always build downwards. The round ball of fibres which she has previously kneaded up with glue she now forms into a leaf, walking backwards, and spreading it out with her mandibles, her tongue, and her feet, till it is as thin almost as tissue paper.

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One sheet, however, of such paper as this would form but a fragile ceiling, quite insufficient to prevent the earth from falling down into the nest. The wasp, accordingly, is not satisfied with her work till she has spread fifteen or sixteen layers one above the other, rendering the wall altogether nearly two inches thick. The several layers are not placed in contact like the layers of a piece of pasteboard, but with small intervals or open spaces between, appearing somewhat like a grotto built with bivalve shells, particularly when looked at on the outside. This is probably caused by the insect working in a curvilineal manner. Having finished the ceiling she next begins to build the first terrace of her city, which, under its protection, she suspends horizontally, and not like the combs in a bee-hive, in a perpendicular position. The suspension of which we speak is also light and elegant, compared with the more heavy union of the hive-bee's comb. It is in fact a hanging floor, immoveably secured by rods of similar materials with the roof, but rather stronger. From twelve to thirty of these rods, about an inch or less in length, and a quarter of an inch in diameter, are constructed for the suspension of the terrace. They are elegant in form, being made gradually narrower towards the middle and widening at each end, in order no doubt to render their hold the stronger. The terrace itself is circular, and composed of an immense number of cells formed of the paper already described, and of almost the same size and form as those of a honeycomb, each being a perfect hexagon, mathematically exact, and every hair's breadth of the open space completely filled. These cells, however, are not used as honey-pots by wasps as they are by bees, for wasps, certain foreign species excepted, make no honey, and the cells are wholly appropriated to the rearing of their young. The grubs, like those of other hymenopterous insects, are placed with their heads downwards, and the openings of the cells are also downwards, while their united bottoms form a nearly uniform level upon which the inhabitants of the nest may walk. In the case of the carder-bee, when the young one has escaped from its cradle-cell, that cell is subsequently appropriated to the storing of honey. But in the case of wasps, a cell thus evacuated is immediately cleaned out and repaired for the reception of another grub-an egg being laid in it, as soon as it is ready, by a female wasp. When the foundress-wasp has completed a certain number of cells and deposited eggs in them she soon intermits her building operations in order to procure food for the young grubs which now require all her care. Their food consists principally of flies and other insects. In due time the grubs which were early hatched cease to feed, and spin a cover over

their cells; they then change to perfect insects, and lend their assistance in the extension of the edifice, enlarging the original coping of the foundress by side walls and forming another platform of cells, suspended to the first by columns, as that had been suspended to the ceiling. In this manner several platforms of combs are constructed, the outer walls being extended at the same time, and by the end of the summer there are generally from twelve to fifteen platforms of cells. The cells constructed towards the end of the season are larger than those of the earlier made platforms; these are intended for the purpose of rearing the grubs which will become male and female wasps. In all but the late-constructed cells neuter wasps are produced. These are the workers, the males, like the drones of a bee-hive, performing no menial service. Each platform contains upwards of 1000 cells, so that in a vespiary there would be more than 15,000 cells. Réaumur has calculated that a single nest may produce every year more than 30,000 wasps, reckoning only 1000 cells, and each serving successively for the cradle of three generations. But although the whole structure, we again quote Mr. Rennie, is built at the expense of so much labour and ingenuity, it has scarcely been finished before the winter sets in, when it becomes nearly useless, and serves only for the abode of a few benumbed females, who abandon it on the approach of spring and never return; for wasps do not, like mason-bees, ever make use of the same nest for more than one season.

We must not dwell longer on instances of burrowing animals, but must refer the reader to Mr. Wood's book, where he will find much curious information, and many admirable illustrations.*

Of British mammalia that construct pensile homes in which to rear their young or to inhabit, the harvest-mouse and squirrel are instances. Of this first-named beautiful little animal and its nest, there is an admirable illustration at page 195 of Mr. Wood's work:

The harvest-mouse surpasses all its congeners in the beauty and elegance of its home, which is not only constructed with remarkable neatness, but is suspended above the ground in such a manner as to entitle it to the name of a true pensile nest. Generally it is hung to several stout grass-stems; sometimes it is fastened to wheat-straws; and

* Mr. Wood arranges animal habitations under the following heads :1. Burrows. 2. Pensile homes. 3. Real buildings or domiciles formed of mud, stones, sticks, &c. 4. Sub-aquatic habitations. 5. Social habitations. 6. Those which are formed parasitically on animals or plants. 7. Homes built on branches. 8. Miscellaneous habitations. It is evident that such a classification of animal habitations according to their principle of construction is confused, and that the divisions run frequently one into the other.

in one case, mentioned by Gilbert White, it was suspended from the head of a thistle. It is a very beautiful structure, being made of very narrow grasses and woven so carefully as to form a hollow globe, rather larger than a cricket ball and very nearly as round. How the little creature contrives to form so complicated an object as a hollow sphere with thin walls is still a problem. It is another problem how the young are placed in it, and another how they are fed. The walls are so thin that an object inside the nest can be easily seen from any part of the exterior, there is no opening whatever, and when the young are in the nest they are packed so tightly that their bodies press against the wall in every direction. As there is no defined opening, and as the walls are so loosely woven, it is probable that the mother is able to push her way between the meshes, and so to arrange or feed her young.

The common squirrel of our country constructs two kinds of homes, a winter residence for hibernation, and a summer one for itself and young.

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These two nests are as different as a town mansion and a shootingbox: the former being strong, thick-walled, sheltered, and warm; and the other light and airy. The winter cage is almost invariably placed in the fork of some tree, generally where two branches start from the trunk. It is well concealed by the boughs on which it rests, and which serve also as a shelter from the wind. The summer cage, on the contrary, is comparatively frail, and is placed nearly at the extremity of slender boughs, which bend with its weight, and cause the airy cradle to rock and dance with every gust of wind.'

Of birds that fabricate pensile nests of various forms and materials there are numerous examples, occurring, however, generally in hot countries. The members of the Ploceidae (weaverbirds), a sub-family of Fringillidæ, are conspicuous as builders of suspended nests.

All the pensile birds are remarkable for the eccentricity of shape and design which marks their nests, although they agree in one point, namely, that they dangle at the end of twigs and dance about merrily at each breeze. Some of them are very long, others are very short, some have their entrance at the side, others from below, and others again from near the top; some are hung hammock-like, from one twig to another; others are suspended to the extremity of the twig itself; while others that build in the palms, which have no true branches and no twigs at all, fasten their nests to the extremity of the leaves. Some are made of various fibres and others of the coarsest grass straws; some are so loose in their texture that the eggs can be plainly seen through them, while others are so strong and thick that they almost look as if they were made by a professional thatcher.'

The object of the weaver-birds in selecting the ends of twigs, seeds, palm leaves, &c., and very frequently in suspending their

nests

nests over water, is that they may baffle the designs of thievish monkeys, or other enemies, upon the eggs and young. Opposite page 201 there is a spirited plate of monkeys, weaver-birds, and nests. The following account of the weaver-birds engaged in nest building was supplied to Mr. Wood by an eye-witness. The species mentioned is the Ploceus ocularius, a smallish yellow bird, which makes its nest in the shape of a chemist's retort, or like a very large horse-pistol suspended by the butt.

The bird that builds these nests is colonially termed the yellow oriole. The ingenious little creature is nearly as large as a thrush, and is of a bright yellow colour, except the ends of the wings, which are of a brownish hue. It is gregarious, and when a good locality has been found, several hundred nests will be suspended from some dozen trees within a few yards of each other. The most pliant branches are invariably selected from which the nest is suspended, and in all cases the end of the nest overhangs the stream, so that any additional weight would bring the nest into the water. The birds make a great disturbance when building, there being usually a regular fight in order to secure the best places. In building the birds first commence by working some stout flags or reeds from the branch, so as to hang downwards. They then attach the upper part of the nest to the branch, so as to form the dome-like roof. By degrees they complete the globular bulb, still working downwards, and lastly, the neck is attached to the body of the nest. Great skill is required to keep the neck even and open, and yet no machine could accomplish the work better than do these ingenious little architects. The upper part of the nest is very thick and firmly built, more than twice as thick as the neck, and the material of which it is made is far stronger. In some cases I have seen one nest attached to another; and when this is the case, the second builder strengthens the first nest, and then attaches his own thereto. Should by chance a hawk or monkey venture into the vicinity of a colony of birds, it is chased and chirped at by hundreds of these little creatures, who make common cause against the intruder, and quickly drive him off. During the building of the nests the river side is a most interesting place, as the intelligence and diligence of the birds are most remarkable.'

Perhaps the little tailor-bird of India and Ceylon is as wonderful an instance of architectural skill as can be found amongst birds. Using her beak as a needle, the tailor-bird stitches for herself and little ones a comfortable home.

The manner in which it constructs its pensile nest is very singular. Choosing a convenient leaf, generally one which hangs from the end of a slender twig, it pierces a row of holes along each edge; using its beak in the same manner that a shoemaker uses his awl, the two instruments being very similar to each other in shape, though not in material. These holes are not all regular, and in some cases there

are