enable them to resist the wind, to which they are so fully exposed.

These spiders have, moreover, a most singular plan of strengthening their web, when the wind is more than ordinarily violent. If they find that the wind stretches their nets to a dangerous extent, they hang pieces of wood, or stone, or other substances to the web, so as to obtain the needful steadiness. I have seen a piece of wood which had been thus used by a Garden Spider, and which was some two inches in length and thicker than an ordinary drawing-pencil. The spider hauled it to a height of nearly five feet; and when by some accident the suspending thread was broken, the little creature immediately lowered itself to the ground, attached a fresh thread, ascended again to the web, and hauled the piece of wood after it.

It found this balance-weight at some distance from the web, and certainly must have dragged it for a distance of five feet along the ground before reaching the spot below the web. There were eight or ten similar webs in the same verandah, but only in the single instance was the net steadied by a weight.

The structure of the beautiful web is very remarkable.

It is nearly circular, and is composed of a number of straight lines, radiating from a common centre, and having a spiral line wound regularly upon them. Now, the structure of the radiating and the spiral lines is quite distinct, as may be seen by applying a microscope of moderate power. The radiating lines are smooth and not very elastic, whereas the spiral line is thickly studded with minute knobs, and is elastic to a wonderful degree, reminding the observer of a thread of India-rubber. So elastic, indeed, is this line, that many observers have thought that the spider has the power of retracting them within the spinnerets, inasmuch as she often will draw a thread out to a considerable length, and then, when she approaches the point to which it will be attached, it seems to re-enter the spinneret until it is shortened to the required length. This, however, is only an optical delusion, and caused by the great elasticity of the thread, which can accommodate itself to the space which it is required to cross.

It is to the little projections that the efficacy of the net is due, for they are composed of a thick, adhesive, and viscid substance, and serve to arrest the wings and legs of the insects that happen to touch the net. In his splendid work on the British Spiders,

Mr. Blackwell has the following remarks upon the structure of the threads:"As the radii are unadhesive, and possess only a moderate share of elasticity, they must consist of a different material from that of the viscid spiral line, which is elastic in an extraordinary degree. Now, the viscidity of this line may be shown to depend entirely upon the globules with which it is studded, for if they be removed by careful application of the finger, a fine glossy filament remains, which is highly elastic, but perfectly unadhesive. As the globules, therefore, and the line on which they are disposed, differ so essentially from each other and from the radii, it is reasonable to infer that the physical constitution of these several portions of the net must be dissimilar.

An estimate of the number of viscid globules distributed on the elastic spiral line in a net of Epeira apoclisa of a medium size, will convey some idea of the elaborate operations performed by the Epeira in the construction of their snares. The mean distance between two adjacent radii in a net of this species, is about seven-tenths of an inch; if therefore the number seven be multiplied by twenty, the mean number of viscid globules which occur on one-tenth of an inch of the elastic spiral line, at the ordinary degree of tension, the product will be 140, the mean number of globules deposited on seven-tenths of an inch of the elastic spiral line. This product multiplied by twentyfour, the mean number of circumvolutions described by the elastic spiral line, gives 3,360, the mean number of globules contained between two radii; which, multiplied by twenty-six, the mean number of radii, produces 87,360, the total number of viscid globules in a finished net of average dimensions.

A large net, fourteen or sixteen inches in diameter, will be found by a similar calculation to contain upwards of 120,000 viscid globules, and yet Epeira apoclisa will complete its snare in about forty minutes if it meet with no interruption."

These calculations will serve to show the elaborate nature of the webs which we see constantly in our gardens, as well as their value to the architect. The secretion of the liquid from which the lines proceed is a work of time, so that if a spider is forced to spin several nets in rapid succession, it loses all its silk and cannot make a web. To wait until a fresh supply should be secreted would be a terrible privation, and moreover, the want of food would stop the secretion, so that the spider has no

other resource than to make war on a weaker spider, drive him out of his net and usurp possession thereof. Such being the case, the spiders are all very chary of using their silk, and never trouble themselves to make webs when a storm is impending They are therefore very excellent barometers, and if the spiders all take to mending their nets or spinning new webs, fine weather is always at hand.

One very remarkable point in the construction of these webs, so exactly true in all their proportions, is that they are executed entirely by the sense of touch. The eyes are situated on the front of the body and on the upper surface, whereas the spinnerets are placed at the very extremity of the body and on the under surface, the threads being always guided by one of the hind legs, as may be seen by watching a garden spider in the act of building or repairing her web. In order that the fact should be placed beyond a doubt, spiders have been confined in total darkness, and yet have spun webs which were as true and as perfect as those which are made in daylight.

A PECULIARLY beautiful pensile cocoon is constructed by a common British spider, scientifically termed Agelena brunnea, but which has no popular name. It is really remarkable that, considering the great number of species which inhabit England, so very few should have been sufficiently distinguished to receive popular names. Owing, in all probability, to the foolish dislike towards spiders entertained by most persons. a dislike which has been instilled into their minds at a very early age, these wonderful and interesting creatures are seldom watched, and there are very few persons who really know one spider from another, or who have any idea of their exceeding usefulness when in the places which they were intended to inhabit. Spiders are certainly out of their place in a room, and the housemaid is perfectly justified in exterminating them, but in the garden or the field they should never be injured, but rather encouraged as much as possible.

The species whose beautiful nest will now be described is generally to be found upon commons, especially where gorse is abundant, as it generally hangs its nest to the prickly leaves of that shrub. The cocoon is shaped rather like a wine glass, and is always hung with the mouth downwards, being fastened by the stalk to a leaf or twig of the gorse. It is very small, only

measuring a quarter of an inch in diameter, and when it is first made, is of the purest white, so as to be plainly visible among the leaves.

This purity, however, it retains but a very short time, for after the spider has deposited her eggs, which are quite spherical, and about forty or fifty in number, she closes the mouth of the cocoon and proceeds to daub it all over with mud. The moistened earth clings tightly to the silken cocoon, and disguises it so effectually that no one who had not seen it before that operation, could conceive how beautiful it had once been. The muddy cover certainly makes the cocoon less visible, and may probably have another effect, that of protecting the inclosed eggs and young from the attacks of insects that feed upon spiders. Several other species have the habit of daubing their beautiful cocoons with mud.

This species is plentiful in Bostal Common and Bexley Heath in Kent, the profuse growth of gorse being very suitable to its mode of life, and I have several specimens of their nests taken from Shooter's Hill. June is the best month for them, as they may be found both before and after the mud has been applied.

An allied species, Agelena labyrinthica, is equally plentiful in similar localities, where its curious webs may be seen stretched in horizontal sheets over the gorse, and having attached to each web a cylindrical tube, at the end of which sits the spider itself. Heath and common grass are also frequented by this spider.

Besides the net or web in which it lives, and by means of which it catches prey, it makes a beautiful cocoon in which the eggs are placed. Externally the cocoon looks like a simple silken bag, perfectly white in colour, and, except in size, somewhat resembling that of the preceding species. It is only when quite freshly made, that the white hue of the cocoon is visible; for after its completion, it is covered with scraps of dry leaves, bark, earth, and other substances. If, however, this cocoon be opened, it is found to contain at least another cocoon within, and often comprises two, of a saucer-like shape, and made also of white silk. These inner cocoons are nearly half an inch in diameter, and contain a very variable quantity of pale yellow, spherical eggs, sometimes fifty in number, but often exceeding a hundred. The inner cocoons are firmly tied by strong lines to the interior of the large sac in which they are inclosed.

CHAPTER XV.

BUILDERS

Building Mammalia-Definition of the title-Inferiority of the manımalia as architects-The BRUSH-TAILED BETTONG-its structure and colour--The Nest of the Bettong, and its adaptation to the locality-Singular method of conveying materials-Its nocturnal habits-The RABBIT-EARED BANDICOOT, and its habitat―The generic title-Curious form of the ears and feet-Difficulty in discovering its nest-The MUSQUASH or ONDATRA-Its general habits-Its burrowing powers, and extent of its tunnels-The Musquash as a builderForm and size of its house-Mode of killing the animal by spear, gun, and trap -Its flesh and fur.

WE now take our leave of the Pensiles, and pass to those animals which build, rather than burrow or weave. The materials used by the Builders are variable. In the most perfect examples, earth is the material that is employed, but in many instances other substances such as wood, earth, and sticks are used by the architect.

As a general rule, the mammalia are by no means notable for their skill in the construction of their houses. In making burrows they far excel all the other vertebrates both in the length of the tunnels and in the elaborate arrangement of the subterranean domicile. The mole, for example, is pre-eminent as a burrower and as a subterranean architect, and there are many of the rodents which drive a whole labyrinth of tunnels. through the soil. But they are very indifferent builders, and with a few exceptions are unable to raise an edifice of any kind, or to weave a nest that deserves the name.

Our list of Building Mammalia will therefore be a short one, comprising only three species, two inhabiting Australia and one a native of America.

THE first example of the Building Mammalia is the PENCILLED BETTONG (Bettongia pencillata), sometimes called the BRUSHTAILED BETTONG, and often known by the name of JERBOA