where it is divested of the chaff and packed away. This chaff is taken out, and thrown beyond the limits of the housed area." We are, moreover, told that when the grain happens to become damp, it is carried out and exposed to the sun on the first fine day to dry, and is then returned again to the store. This looks as like human instinct as well can be.

The ants even let their fields go fallow for a time, and commence sowing again at a regular season. Great care is taken by them to select spots for their farms which are not intruded upon by graminivorous animals. Thus the turn rows in arable fields are selected as places where they are little likely to be disturbed. This account of the habits of the agricultural ant has little to do with his homebuilding capabilities, but it is so curious that the reader will readily excuse the digression.

The driver ant of Western Africa is another very extraordinary creature. This insect is a builder, it is true, but it employs its art in making a kind of covered way to protect it from the sun whilst moving from place to place. These ants, when upon their march, are the terror of every living thing they come in contact with. The natives desert their villages, knowing that the army never deviates from its line of march, and that it devours everything in its way. They never cross water when they can avoid it, but when it is compulsory upon them to do so they never hesitate. They manage to complete a suspension bridge from tree to tree of their bodies, in the following ingenious manner.

First,

a single ant clings tightly to a branch, and then a second insect crawls cautiously down its suspended body, and hangs to its long outstretched limbs. Others follow in rapid succession, until they form a complete chain of ants, which swing about in the wind. One of the largest workers then takes its stand immediately below the chain, holds firmly to the branch with its hind limbs, and dexterously catches with its fore-legs the end of the living chain as it swings past. The ladder is thus completed and fixed ready for the transit of insects. When water has to be crossed the ants cling to each other, and thus form a floating raft, the free end of which is swept by the stream against the opposing bank, where the last ant anchors, and the living pontoon is thus prepared for the passage of the main army. The natives have a story to the effect that even the great python is so fearful of these armies of driving ants that, after it has crushed its prey, it makes a long circuit, at least a mile in diameter, in order to see if an army of these insects is abroad, knowing that, if such is the case, they are sure to make towards it in order to devour it. The python, there

fore, deserts her meal, fearing possibly that, whilst gorged and helpless, she may herself fall a victim to these creatures, which resolutely attack snakes, first biting their eyes, and thus rendering them helpless victims, bound in darkness to one spot.

In the ant-lion we have another insect whose habitation combines in one the character of a trap, as well as a home. This singular creature selects a sandy spot, into which he digs a conical pit, throwing up the sand with its hind legs as it progresses with its work. In this manner, it excavates a sand trap about three inches in diameter, at the bottom of which it hides itself and waits for its prey. Insects of all kinds are an inquisitive race, running to and fro, and carefully and patiently trying all things; consequently when any of them approach the ant-lion's trap, and peep into it, the treacherous sand gives way, and the doomed creature slides down right into the ant-lion's mouth. How many traps men set for each other, and how easily we slide into them we too well know, therefore we need not preach a sermon to poor little insects upon the folly of heedlessness.

There is a spider which constructs a home and a trap in one, but upon different principles; the ant-lion may be likened to a medical quack, whose artful pitfall leads you to slide down to ruin gently. The trap-door spider, on the other hand, snaps his victim up sharp, without any preliminary struggle. This curious creature inhabits many parts of the world, but the best specimens, of the class are to be found in Jamaica and Australia. It makes a tunnel in a sloping bank, and to this tunnel it fits a lid, so beautifully constructed, that it closes without giving any evidence of existence to the creature passing by it. The hole, Mr. Wood tells us, is bevelled inwards as truly as though it had been turned, and the lid fits with a nicety that could not be beaten by the cleverest human workman. The hinge by which the trap is fastened is also a specimen of splendid workmanship, and fits the orifice with perfect truth. The creature, which is very largebodied, and from its likeness to a crustacean, is called the crab spider, sits at the entrance, with the lid sufficiently opened to allow of its seeing anything near, and immediately it does so, out it rushes and drags in its victim, banging-to the trap with a perceptible click. There is a specimen of this spider's trap-nest in the nest-room of the British Museum, which has a trap-door at either side of the tunnel.

There are two other spiders, whose habitations and habits are so extraordinary, that our readers cannot fail to feel an interest in Mr. Wood's account of them. The pirate spider

its colour being a chocolate brown, marked with a broad orange band, which outlines its abdomen and thorax. The still more remarkable water-spider, whose habits partake of those of the water-beetle, is also a native of our island. This creature builds its home in the water, and lives a sub-aqueous life. Its nest, which is made of silk, and woven quite water-tight, is generally attached to the leaf of some water-plant. As this spider breathes the air, it was long a puzzle how it stored its submerged cell with air, some naturalists thinking that what had been found in its nests had been exuded from the plants; the observations of Mr. Bell, made upon some of these captured spiders, give a most interesting answer to the question. After building its cell, which is about the size of half-anacorn, the rounded part being uppermost, it stocked it with air in the following curious manner:-"As soon as it comes to the surface of the water it turns with the extremity of its abdomen upwards, and exposes a portion of the body to the air for an instant; then, with a jerk, it snatches, as it were, a bubble of air, which is not only attached to the hairs which cover the abdomen, but is held on by the two hinder legs, which are crossed at an acute angle near their extremity, this crossing of the legs taking place at the instant the bubble is seized. The little creature then descends more rapidly and regains its cell,

scarce, the dealers who

furnish a

quaria ransacking every pool for it, and charging a high price for the treasure to their customers.-What strikes the general reader, who has no intimate knowledge of the infinite methods

by

which nature

works, as made known

to us by her creatures, is the apparent inadaptibility of certain living things to the work they have to do. For instance, what creature seems to be less adapted to boring holes in the hard rock than the snail, yet it is without doubt that a mollusc, termed the boring-snail, very like the common banded snail of the hedges, does work its way into very hard rock. There is a little wood in Picardy, known as Le Bois des Bochus, in which the stone is found that built the column at Boulogne. It is very hard, yet these boring snails have managed to excavate to half-an-inch in depth, sufficient to give shelter to the creature's body. It is supposed that the foot of the snail secretes an acid which dissolves the stone, but this has by no means been proved. There is, however, a mollusc which is a very notable borer, and which makes it way deep into the rock. The pholas, popularly known as the piddock, has indeed riddled our chalk cliffs with its holes. Its shell is the instrument with which it works. Although extremely fragile, it is covered with ridges, which work into the rock like a boring-tool. This little creature is an active agent in producing the disintegration of the rocks bordering the ocean, and to its agency many of the changes that are ever going on along our sea-coasts may be ascribed. The wood-boring pholas, more popularly known as the ship-worm, may be considered, however, the typical borer. The

ravages which this creature makes among shipping renders it the terror of the mariner. It destroys thick beams of wood as noiselessly and as unobserved as the white ant; and, like that creature, it lines its tunnel with a calcareous lining of great strength. The visitor to the South Kensington Museum will find some most extraordinary specimens of ship's timbers, so bored in every direction by this creature, that scarcely a bit of vegetable matter is to be found remaining.

The great teredo produces a shell more than five feet in length and three inches in diameter, the substance of the shell being halfan-inch in thickness; they look, in fact, like hollow stalactites. These curious tunnelshaped homes, lined with its internal casing, gave the hint upon which the engineer worked in the construction of the Thames Tunnel.

It seems odd to refer to fishes as examples of nest-builders; but there is a little creature that most of us have hooked, with a bent pin, from the ponds or ditches in the country-the stickleback, that is a very notable specimen of an aquatic builder of a "Home without hands." This fierce little fish constructs a nest of the grasses and fresh water algae to be found at the margin of all streams, and it must be remembered that it has only its mouth as a tool to work with. The nest is very loosely woven together, and is used for depositing the eggs. It is well understood, says Mr. Wood, that a certain space around each nest is considered sacred to its occupiers, and if any other fish should venture to intrude within this charmed circle, they rush at it even if ten times its size, with the most undaunted courage, and generally manage to drive it away. There is another fish, in the fresh waters of tropical America, that constructs nests out of grass blades, straws, and leaves, in muddy holes above the water. The fish, known to the natives as the hassar, is, however, very curious in its habits; like an eel, it will travel from one pool to another across the land, and indeed, at certain seasons of the year, like those creatures, it burrows and lives in the mud.

The aptitude of birds as builders we all know; but our readers will be surprised to hear that there is a bird of tropical Americathe red-breasted horn-bill-which "submits to a live confinement; " that is, the female bird, when it enters its nest, which is generally situated in the hollow of a tree, is plastered up by the male, and never leaves her young for three months, during all which time the family are fed by the old bird.

Dr. Livingstone, who gives an account of this bird, in his well-known work, says that

* See Old Series, VOL. I. p. 145.

"she is said sometimes to hatch two eggs, and when the young of these are full-fledged, other two are just out of the egg-shells; she then leaves the nest with the two elder, the surface is again plastered up, and both male and female attend to the wants of the young which are left."

The pensile birds of America afford an example of the multiform methods adopted among the feathered tribe of constructing their homes. Some suspend their nest, just as the sailor does his hammock, by the head and foot, to a branch, like the lanceolate honeyeaters; others, like the saw-bill hummingbird, weave them of long vegetable fibres, like an open-work purse, so that the eggs show through; others again, like the Baya sparrow, construct their nest like a retort, the entrance being from below; whilst the sociable weaver bird of South Africa constructs a nest, which is a wonderful example of bird architecture. These nests are large enough to shelter five or six men. It is not the effort of a single pair of birds, but of the united efforts of a number. It is originally constructed by a single pair, however, who begin their proceedings by hanging bunches of grass over a branch, which acts as a kind of thatch. Under this the first nest is built, and others are speedily attached to it. At last, so many nests are constructed under the sheltering thatch, that there is room for no more. The thatch is now enlarged, and nest after nest is added around its circumference, just as in the combs of a wasp's or hornet's habitation. It must be observed that the entrance to these agglomerations of nests is from below; in fact, the structure looks very like an extended umbrella hanging in the tree, full of holes at the bottom, the entrances to the different nests. In course of time these nests grow so large and become so heavy that, with the addition of the wet they absorb during the rainy season, down they come crashing to the ground.

The bird that most nearly imitates the methods used by man in sewing articles together, is the tailor-bird, which makes a nest as a sempstress would make a pocket. Having selected a convenient leaf, it pierces with its beak a number of holes along one side, using that instrument exactly as a cobbler uses his awl. It then finds some long vegetable fibre and passes it through the holes, drawing the ends of the leaf together until a cone-like hollow is formed, which it lines with a soft white down. In this manner a light and elegant nest is formed, which is not distinguishable from the other leaves of the tree; when one leaf is insufficient for its purpose, another is sewn to it in the same manner.

There are, we are told, several specimens of the nest of the tailor-bird in the British Museum, as well as of other living creatures -a fact we were not aware of before.

With respect to the bee, which we all recognise as a sociable insect, Mr. Wood tells a remarkable story. All observers have noticed the close packing of the cells of this familiar insect, and philosophers have long suspected that they represented, with mathematical accuracy, the truest economy of packing within a given space. But it remained to be proved, and in accomplishing this proof, a very singular fact was evolved. "Many

66

years ago," says Mr. Wood, Maraldi (an eminent mathematician), being struck with the fact that the lozenge-shaped plates always had the same angles, took the trouble to measure them, and found that in each lozenge the large angles measured 109° 28', and the smaller 70° 32', the two together making 180°, the equivalent of two right angles." Reaumur, another mathematician, thinking this uniformity of angle might have some connection with the wonderful economy of space which is observable within the bee's comb, asked Koenig to make the following calculation: "Given, a hexagonal vessel, terminated by three lozenge-shaped plates, what are the angles which would give the greatest amount of space with the least amount of material." The reply was 109° 26' and 70° 34', almost precisely agreeing with the measurement of Maraldi. The difference was so small, that it was considered practically to amount to nothing in the actual construction of a cell, and the bee was accordingly accredited with having solved the mathematical problem. However, Maclaurin, a hard-headed Scotch mathematician, very properly concluded that, in a mathematical question, precision was a necessity. Accordingly he worked

thematician commit the error? "On investigation it

was found that no blame attached to Koenig, but that the error lay in the book of logarithms which he used. Thus a mistake in a mathematical work was accidentally discovered by measuring the angles of a bee-cella mistake sufficiently great to have caused the loss of a ship whose captain happened to use

Of the sociable mammalia, the beaver is, without doubt, the best type. So many idle tales have been told respecting this creature; his building powers have been so exalted, and again so 'detracted from, that it is lucky we have at last specimens of the animal in our Zoological Gardens, and can verify some of its alleged capabilities at least. In its native wilds it builds really very formidable dams, in order to secure a supply of water in all seasons, and it is known that in constructing these barriers it proceeds upon truly engineering principles. Thus, when it has to deal with a sluggish stream, where there is little pressure of water, it builds the dam with logs of wood laid at right angles to the banks, filling up the interstices with mud. But where the stream runs rapidly, and the pressure is great, the dam is constructed in the shape of a V, its apex being directed towards the head of the stream, thus affording the best means of resistance to the weight of water. The speed with which beavers will fell the largest trees, with the aid of its adze-like teeth only, is truly marvellous. A society of beavers will clear in a wood a space of acres of trees: it would seem as though an emigrant had been busy with his adze, or with fire, so great is the