contained the germ of her progeny. The attachment of this affectionate mother is not confined to her eggs. After the young spiders are hatched, they make their way out of the bag by an orifice, which she is careful to open for them, and without which they could never escape: and then, like the young of the Surinam toad, they attach themselves in clusters upon her back, belly, head, and even legs; and in this situation, where they present a very singular appearance, she carries them about with her, and feeds them until their first moult, when they are big enough to provide their own subsistence. I have more than once been gratified by a sight of this interesting spectacle; and, when I nearly touched the mother, thus covered by hundreds of her geny, it was most amusing to see them all leap from her back, and run away in every direction. Kirby and Spence.

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ON THE SPIDER'S WEB.

WHAT, if we had not witnessed it, would seem more incredible, than that any animal should spin threads, weave these threads into nets, more admirable than ever fowler or fisherman fabricated, suspend them with the nicest judgment in the place most abounding in the wished-for prey, and, there concealed, watch patiently its approach? In this case, as in many others, we neglect actions in minute animals, which, in the larger, would excite our endless admiration. How would the world crowd to see a fox, which should spin ropes, weave them into an accurately-meshed net, and extend this net between two trees, for the purpose of entangling a flight of birds! Or should we think we had ever expressed sufficient wonder, at seeing a fish, which obtained its prey by a similar contrivance? Yet there would, in reality, be nothing more marvellous in their procedures, than in those of spiders, which, indeed, the minuteness of the agent renders more wonderful. The thread spun by spiders is in substance similar to the silk of the silkworm, and other caterpillars, but of a much finer quality. As in them, it proceeds from reservoirs

into which it is secreted in the form of a viscid gum. If you examine a spider, you will perceive four or six protuberances or spinners. These are the machinery, through which, by a process more singular than that of rope-spinning, the thread is drawn. Each spinner is furnished with a multitude of tubes, so numerous and so exquisitely fine, that a space often not much bigger than the pointed end of a pin is furnished, according to Reaumur, with a thousand of them. From each of these tubes, consisting of two pieces, the last of which terminates in a point infinitely fine, proceeds a thread of inconceivable tenuity, which, immediately after issuing from it, unites with all the other threads into one. Hence from each spinner proceeds a compound thread; and these four threads again unite, and form the thread we are accustomed to see, which the spider uses in forming its web. Thus a spider's thread, even spun by the smallest species, and when so fine, that it is almost imperceptible to our senses, is not, as we suppose, a single line, but a rope composed of at least four thousand strands. How astonishing! But to feel all the wonder of this fact, we must follow Leeuwenhoek in one of his calculations on the subject. This renowned microscopic observer found, by an accurate estimation, that the threads of the minutest spiders, some of which are not larger than a grain of sand, are so fine, that four millions of them would not equal in thickness one of the hairs of his beard. The spider is gifted by her Creator with the power of closing the orifices of the spinners at pleasure, and can thus, in dropping from a height by her line, stop her progress at any point of her descent. The only other instruments, employed by the spider in weaving, are her feet, with the claws of which she usually guides, or keeps separated into two or more, the line from behind; and, in many species, these are admirably adapted for the purpose, two of them being furnished underneath with teeth, like those of a comb, by means of which the threads are kept asunder. But another instrument was wanting. The spider, in ascending the line, by which she has dropped herself from an eminence, winds up the superfluous cord into a ball. In per

forming this, the pectinated claws would not have been suitable. She is, therefore, furnished with a third claw between the other two, and is thus provided for every occasion.-The situations, in which spiders place their nets, are as various as their construction. Some prefer the open air, and suspend them in the midst of shrubs or plants, most frequented by flies and other small insects, fixing them in a horizontal, a vertical, or an oblique direction. Others select the corners of windows and of rooms, where prey always abounds; while many establish themselves in stables and neglected outhouses, and even in cellars and desolate places, in which one would scarcely expect a fly to be caught in the month.-The most incurious observer must have remarked the great difference, which exists in the construction of spiders' webs. Those, which we most commonly see in houses, are of a woven texture similar to fine gauze, and are appropriately termed webs; while those most frequently met with in the fields are composed of a series of concentric circles, united by radii diverging from the centre, the threads being remote from each other. These last are with greater propriety termed nets, and the insects, which form them, proceeding on geometrical principles, may be called geometricians; while the former can aspire only to the humbler denomination of weavers.-The weaving spider, which is found in houses, having selected some corner for the site of her web, and determined its extent, presses her spinners against one of the walls, and thus glues it to one end of her thread. She then walks along the wall to the opposite side, and there, in like manner, fastens the other end. This thread, which is to form the only margin or selvage of the web, and requires strength, she triples or quadruples, by a repetition of the operation just described; and from it she draws other threads in various directions, the interstices of which she fills up, by running from one to the other, and connecting them by new threads, until the whole has assumed the gauze-like texture which we see. The web just described presents merely a simple horizontal surface, but others, more frequently seen in out-houses and amongst bushes, possess a very artificial appendage. Besides the

main webs, the spider carries up, from its edges and surface, a number of single threads, often to the height of many feet, joining and crossing each other in various directions. Across these lines, which may be compared to the tackling of a ship, flies seem unable to avoid directing their flight. The certain consequence is, that, in striking against these ropes, they become slightly entangled, and, in their endeavours to disengage themselves, rarely escape being precipitated into the net spread underneath for their reception, where their doom is inevitable. But the net is still incomplete. It is necessary that our hunter should conceal her grim visage from the game, for which she lies in wait. She does not, therefore, station herself upon the surface of her net, but in a small silken apartment, constructed below it, and completely hidden from view. But, thus removed from her net, and entirely out of sight of it, how is she to know when her prey is entrapped? For this difficulty our ingenious weaver has provided. She has taken care to spin several threads, from the edge of the net to that of her hole, which at once inform her, by the vibrations, of the capture of a fly, and serve as a bridge, on which in an instant she can run to secure it.— You will readily conceive, that the geometrical spiders, in forming their concentric-circled nets, follow a process very different from that just described; than which, indeed, it is in many respects more curious. As the net is usually fixed in a perpendicular or somewhat oblique direction, in an opening between the leaves of some shrub or plant, it is obvious that, round its whole extent, will be required lines, to which can be attached those ends of the radii, that are farthest from the centre. Accordingly, the construction of these exterior lines is the spider's first operation. She seems careless about the shape of the area which they enclose, well aware that she can as readily inscribe a circle in a triangle as in a square, and, in this respect, she is guided by the distance or proximity of the points, to which she can attach them. She spares no pains, however, to strengthen and keep them in a proper degree of tension. With the former view, she composes each line of five, or six, or even more threads glued together; and, with the latter,

she fixes to them, from different points, a numerous and intricate apparatus of smaller threads. Having thus completed the foundation of her snare, she proceeds to fill up the outline. Attaching a thread to one of the main lines, she walks along it, guiding it with one of her hind feet, that it may not touch in any part, and be prematurely glued, and crosses over to the opposite side, where, by applying her spinners, she firmly fixes it. To the middle of this diagonal thread, which is to form the centre of her net, she fixes a second, which, in like manner, she conveys and fastens to another part of the lines encircling the area. Her work now proceeds rapidly. During the preliminary operations she sometimes rests. But no sooner are the marginal lines of her net firmly stretched, and two or three radii spun from its centre, than she continues her labour so quickly and unremittingly, that the eye can scarcely follow her progress. The radii, to the number of about twenty, giving the net the appearance of a wheel, are speedily finished. She then proceeds to the centre, quickly turns herself round, and pulls each thread with her feet to ascertain its strength, breaking any one that seems defective, and replacing it by another. Next she glues immediately round the centre five or six small concentric circles that are to remain, which she now proceeds to construct. Placing herself at the circumference, and fastening her thread to the end of one of the radii, she walks up that one towards the centre, to such a distance as to draw the thread from her body of a sufficient length to reach to the next. Then, stepping across and conducting the thread with one of her hind feet, she glues it with her spinners to the point in the adjoining radius, to which it is to be fixed. This process she repeats, until she has filled up nearly the whole space, from the circumference to the centre, with concentric circles, distant from each other about two lines. She always, however, leaves a vacant interval around the smallest first-spun circles, that are nearest the centre, but for what end I am unable to conjecture. Lastly, she runs to the centre, and bites away the small cotton-like tuft that unites all the radii, which, being now held together by the circular threads, have thus pro