Chapter IX: The Spider (2)

2. The silk of the spider is inferior to that of the silk-worm both in lustre and strength; and produces less material in proportion, than can be made available for the purposes of the manufacture. The filament of the spider’s-bag can support a weight of only thirty-six grains, while that of the silk-worm will sustain a weight of one hundred and fifty grains. Thus four or five threads of the spider must be brought together to equal one thread of the silk-worm, and as it is impossible that these should be applied so accurately over each other as not to leave little vacant spaces between them, the light is not equally reflected, and the lustre of the material is consequently inferior to that in which a solid thread is used.

3. A great disadvantage of the spider’s silk is, that it cannot be wound off the ball like that of the silk-worm, but must necessarily be carded. By this latter process, its evenness, which contributes so materially to its lustre, is destroyed.

The ferociousness and pugnacity of the spiders are not exaggerated; they fight like furies. Their voracity, too, is almost incredible, and it is very questionable whether the mere collection of flies sufficient to feed a large number of the spiders would not involve an amount of expense fatal to the project as a lucrative undertaking. The strength of the spiders’ filament is, if anything, overstated by Réaumur. Deficiency of lustre arising from the carding of the filaments is common to the spider-fabric and to spun silk; this objection would, perhaps, not be of very great weight but for the decisive calculation by which Réaumur showed the comparative amount of production between the spider and the silk-worm.

The largest cocoons weigh four, and the smaller three grains each; spider-bags do not weigh above one grain each; and, after being cleared of their dust, have lost two-thirds of this weight; therefore the _work of twelve spiders_ equals that of _only one silk-worm_; and a pound of spider-silk would require for its production 27,648 insects. But as the bags are wholly the work of the females, who spin them as a deposit for their eggs, it follows that 55,296 spiders must be reared to yield one pound of silk: yet this will be obtained only from the best spiders; those large ones ordinarily seen in gardens, &c., yielding not more than a twelfth part of the silk of the others. The work of 280 of these would therefore not yield more silk than the produce of one industrious silk-worm, and 663,552 of them would furnish only one pound of silk!

Although Réaumur’s report completely extinguished Mr. Bon’s project in France, it was revived in England two or three times in the early part of the last century. Swift has not neglected to make it a portion of his unrivalled satire against speculators and projectors, in his account of Gulliver’s visit to the Academy of Lagado:

“I went into another room, says he, where the walls and ceilings were all hung round with cobwebs, except a narrow passage for the artist to go in and out. At my entrance he called out to me not to disturb his webs. He lamented the fatal mistake the world had been so long in, of using silk-worms, while we had such plenty of domestic insects, who infinitely excelled the former, because they understood how to weave as well as spin. And he proposed further, that, by employing spiders, the charge of dyeing silk should be wholly saved; whereof I was fully convinced, when he showed me a vast number of flies most beautifully colored, wherewith he fed his spiders, assuring us that the webs would take a tincture from them, and as he had them of all hues, he hoped to suit every body’s fancy, as soon as he could find proper food for the flies, of certain gums, oils, and other glutinous matter to give a strength and consistency to the threads.”

THE INGENUITY OF SPIDERS.--Mr. Thomas Ewbank of New York, in a letter to the Editor of the Journal of the Franklin Institute, bearing date September 20th, 1842, gives us the following interesting description of the ingenuity of the Spider.

“The resources of the lower animals have often excited admiration, and though no comprehensive and systematic series of observations have yet been made upon them(?), the time is, I believe, not distant when the task will be undertaken--perhaps within the next century. But whenever and by whomsoever accomplished, the mechanism of animals will then form the subject of one of the most interesting and _useful_ volumes in the archives of man.

“Among insects, spiders have repeatedly been observed to modify and change their contrivances for _ensnaring their prey_. Those that live in fields and gardens often fabricate their nets or webs vertically. This sometimes occurs in locations where there is no object sufficiently near to which the lower edge or extremity of the web can properly be braced; and unless this be done, light puffs or breezes of wind are apt to blow it into an entangled mass. Instead of being spread out, like the sail of a ship, to the wind, it would become clewed over the upper line, or edge, like a sail when furled up. Now how would a human engineer act under similar circumstances? But ere the reader begins to reflect(!), he should bear in mind that it would not do to brace the web by running rigging from it to some _fixed_ or immovable object below--by no means;--for were this done, it could not yield to impulses of wind; the rigging would be snapped by the first blast, and the whole structure probably destroyed.

“Whatever contrivances human sagacity might suggest, they could hardly excel those which these despised engineers sometimes adopt. Having formed a web, under circumstances similar to those to which we have referred, a spider has been known to descend from it to the ground by means of a thread spun for the purpose, and after selecting a minute pebble, or piece of stone, has coiled the end of the thread round it. Having done this, the ingenious artist ascended, and fixing himself on the lower part of the web, hoisted up the pebble until it swung several inches clear of the ground. The cord to which the weight was suspended was then secured by additional ones, running from it to different parts of the web, which thus acquired the requisite tension, and was allowed, at the same time, to yield to sudden puffs of wind without danger of being rent asunder.

“A similar instance came under my notice a few days ago. A large spider had constructed his web, in nearly a vertical position, about six feet from the ground, in a corner of my yard. The upper edge was formed by a strong thread, secured at one end to a vine leaf, and the other to a clothes line. One part of the lower edge was attached to a Penyan sun-flower, and another to a trellis fence, four or five feet distant. Between these there was no object nearer than the ground, to which an additional brace line could be carried; but two threads, a foot asunder, descended from this part of the web, and, eight or ten inches below it, were united at a point. From this point, a single line, four or five inches long, was suspended, and to its lower extremity was the weight, a _living one_, viz. a worm, _three inches long_, and _one-eighth of an inch thick_. The cord was fastened around the middle of the victim’s body, and as no object was within reach, all its writhings and efforts to escape were fruitless. Its weight answered the same purpose as a piece of inanimate matter, while its sufferings seemed not in the least to disturb the unconcerned murderer, who lay waiting for his prey above.

“Whether the owner of the web found it a more easy task to capture this unlucky worm and raise it, than to elevate a stone of the same weight, may be a question(?). Perhaps in seeking for the latter, the former fell in his way, and was seized as the first suitable object that came to hand--like the human tyrant, (Domitian) who, to show his skill in archery, planted his arrows in the heads of men or cattle, in the absence of other targets. It may be, however, that a piece of stone, earth, or wood, of a suitable weight, was not in the vicinity of the web.

“To observe the effect of this weight, I separated, with a pair of scissors, the thread by which it was suspended, and instantly the web sunk to half its previous dimensions--the lower part became loose, and with the slightest current kept shaking like a sail shivering in the wind. A fresh weight was not supplied by the next morning; but instead of it two long brace lines extended from the lower part of the web to two vine tendrils, a considerable distance off. These I cut away to see what device would be next adopted, but on going to examine it the following day, I found the clothes line removed, and with it all relics of the insect’s labors had disappeared.”

MASON-SPIDERS.--A no less wonderful structure is composed by a sort of spiders, natives of the tropics and the south of Europe, which have been justly called mason-spiders by M. Latreille. One of these (_Mygale nidulans_, WALCKN.), found in the West Indies, “digs a hole in the earth obliquely downwards, about three inches in length, and one in diameter. This cavity she lines with a tough thick web, which, when taken out, resembles a leathern purse; but what is most curious, this house has a door with hinges, like the operculum of some sea-shells, and herself and family, who tenant this nest, open and shut the door whenever they pass and repass. This history was told me,” says Darwin, “and the nest, with its door, shown me by the late Dr. Butt, of Bath, who was some years physician in Jamaica[175].”

[175] Darwin’s Zoonomia, i. 253, 8vo. ed.

“The nest of a mason-spider, similar to this,” says Mr. Rennie, “has been obligingly put into our hands by Mr. Riddle of Blackheath. It came from the West Indies, and is probably that of Latreille’s clay-kneader (_Mygale cratiens_), and one of the smallest of the genus. We have since seen a pair of these spiders in possession of Mr. William Mello, of Blackheath. The nest is composed of very hard argillaceous clay, deeply tinged with brown oxide of iron. It is in form of a tube, about one inch in diameter, between six and seven inches long, and slightly bent towards the lower extremity--appearing to have been mined into the clay rather than built. The interior of the tube is lined _with a uniform tapestry of silken web, of an orange-white color_, with a texture intermediate between India paper and very fine glove leather. But the most wonderful part of this nest is its entrance, which we look upon as the perfection of insect architecture. A circular door, about the size of a crown piece, slightly concave on the outside and convex within, is formed of more than a dozen layers of the same web which lines the interior, closely laid upon one another, and shaped so that the inner layers are the broadest, the outer being gradually less in diameter, except towards the hinge, which is about an inch long; and in consequence of all the layers being united there, and prolonged into the tube, it becomes the thickest and strongest part of the structure. The elasticity of the materials, also, gives to this hinge the remarkable peculiarity of acting like a spring, and shutting the door of the nest spontaneously. It is, besides, made to fit so accurately to the aperture, which is composed of similar concentric layers of web, that it is almost impossible to distinguish the joining by the most careful inspection. To gratify curiosity, the door has been opened and shut hundreds of times, without in the least destroying the power of the spring. When the door is shut, it resembles some of the lichens (_Lecidea_), or the leathery fungi, such as _Polyporus versicolor_ (MICHELI), or, nearer still, the upper valve of a young oyster-shell. The door of the nest, the only part seen above ground, being of a blackish-brown color, it must be very difficult to discover.”

Another mason-spider (_Mygale cœmentaria_, LATR.), found in the south of France, usually selects for her nest a place bare of grass, sloping in such a manner as to carry off the water, and of a firm soil, without rocks or small stones. She digs a gallery a foot or two in depth, and of a diameter (equal throughout) sufficient to admit of her easily passing. She lines this _with a tapestry of silk glued to the walls_. The door, which is circular, is constructed of many layers of earth kneaded, and bound together with _silk_. Externally, it is flat and rough, corresponding to the earth around the entrance, for the purpose, no doubt, of concealment: on the inside it is convex, _and tapestried thickly with a web of fine silk_. The threads of this door-tapestry are prolonged, and strongly attached to the upper side of the entrance, forming an excellent hinge, which, when pushed open by the spider, shuts again by its own weight, without the aid of spring hinges. When the spider is at home, and her door forcibly opened by an intruder, she pulls it strongly inwards, and even where half-opened often snatches it out of the hand; but when she is foiled in this, she retreats to the bottom of her den, as her last resource[176]. The nest of this spider (the mason spider) is represented in Plate IV. Fig. 14., and shows the nest shut. Fig. 15., represents it open. Fig. 16. the spider (_Mygale cœmentaria_). Fig. 17. the eyes magnified. Figures 18 and 19 parts of the foot and claw magnified. Rossi ascertained that the female of an allied species (_Mygale sauvagesii_, LATR.), found in Corsica, lived in one of these nests, with a numerous posterity. He destroyed one of the doors to observe whether a new one would be made, which it was; but it was fixed immoveably, without a hinge; the spider, no doubt, fortifying herself in this manner till she thought she might re-open it without danger[177].

[176] Mém. Soc. d’Hist. Nat. de Paris, An. vii.

[177] Mém. Soc. d’Hist. Nat. de Paris, An. vii. p. 125, and Latreille,
Hist. Nat. Génér. viii. p. 163.

“The Rev. Revett Shepherd has often noticed, in the fen ditches of Norfolk, a very large spider (the species not yet determined) which actually forms a _raft_ for the purpose of obtaining its prey with more facility. Keeping its station upon a ball of weeds about three inches in diameter, probably held together by slight silken cords, it is wafted along the surface of the water upon this floating island, which it quits the moment it sees a drowning insect. The booty thus seized it devours at leisure upon its raft, under which it retires when alarmed by any danger[178].” In the spring of 1830, Mr. Rennie found a spider on some reeds in the Croydon Canal, which agreed in appearance with Mr. Shepherd’s.

[178] Kirby and Spence, Intr. i. 425.

Among our native spiders there are several, which, not contented with a web like the rest of their congeners, take advantage of other materials to construct cells where, “_hushed in grim repose_,” they “expect their insect prey.” The most simple of those spider cells is constructed by a longish-bodied spider (_Aranea holosericea_, LINN.), which is a little larger than the common hunting spider. It rolls up a leaf of the lilac or poplar, precisely in the same manner as is done by the leaf-rolling caterpillars, upon whose cells it sometimes seizes to save itself trouble, having first expelled, or perhaps devoured, the rightful owner. The spider, however, is not satisfied with the tapestry of the caterpillar, _but always weaves a fresh set of her own_, more close and substantial.

Another spider, common in woods and copses (_Epeira quadrata?_) weaves together a great number of leaves to form a dwelling for herself, and in front of it she spreads her toils for entrapping the unwary insects which stray thither. These, as soon as caught, are dragged into her den, and stored up for a time of scarcity. Here also her eggs are deposited and hatched in safety. When the cold weather approaches, and the leaves of her edifice wither, she abandons it for the more secure shelter of a hollow tree, where she soon dies; but the continuation of the species depends upon eggs, deposited in the nest before winter, and remaining to be hatched with the warmth of the ensuing summer.

The spider’s den of united leaves, however, which has just been described, is not always useless when withered and deserted; for the dormouse usually selects it as a ready-made roof for its nest of dried grass. That those old spiders’ dens are not accidentally chosen by the mouse, appears from the fact, that out of about a dozen mouse-nests of this sort found during winter in a copse between Lewisham and Bromley, Kent (England), every second or third one was furnished with such a roof.

THE WATER SPIDER.--We extract the following exquisitely beautiful and interesting fact in nature, _connected with diving operations_, from the Rev. Mr. Kirby’s Bridgewater Treatise:--

“The Water Spider is one of the most remarkable upon whom that office (diving) is developed by her Creator. To this end, her instinct instructs her to fabricate a kind of _diving-bell_ in the bosom of that element. She usually selects still waters for this purpose. Her house is an _oval cocoon_, filled with air, and lined with _silk_, from which threads issue in every direction, and are fastened to the surrounding plants; in this cocoon, which is open below, she watches for her prey, and even appears to pass the winter, when she closes the opening. It is most commonly, yet not always, entirely under water; but its inhabitant has filled it with air for her respiration, which enables her to live in it. She conveys the air to it in the following manner: she usually swims upon her back, when her abdomen is enveloped in a bubble of air, and appears like a globe of quicksilver[179]; with this she enters her cocoon, and displacing an equal mass of water, again ascends for a second lading, till she has sufficiently filled her house with it, so as to expel all the water.

“The males construct similar habitations by the same manœuvres. How these little animals can envelope their abdomen with an air-bubble, and retain it till they enter their cells, is still one of Nature’s mysteries that have not been explained.

“We, however, cannot help admiring, and adoring, the wisdom, power, and goodness manifested in this singular provision, enabling an animal that breathes the atmospheric air, to fill her house with it under water, and which has instructed her in a secret art, _by which she can clothe part of her body with air as a garment_, and which she can put off when it answers her purpose.

“This is a kind of attraction and repulsion which mocks all our inquiries.”

[179] Her singular economy was first, we believe, described by Clerck
(Aranei Suecici, Stockholm, 1757.), L. M. de Lignac (Mém. des
Araign. Aquat., 12mo. Paris, 1799.), and De Geer.

“The shining appearance,” says Clerck, “proceeds either from an
inflated globule surrounding the abdomen, or from the space between
the body and the water. The spider, when wishing to inhale the air,
rises to the surface, with its body still submersed, and only the
part containing the spinneret rising just to the surface, when it
briskly opens and moves its four teats. A thick coat of hair keeps
the water from approaching or wetting the abdomen. It comes up for
air about four times an hour or oftener, though I have good reason
to suppose it can continue without it for several days together.

“I found in the middle of May one male and ten females, which I
put into a glass filled with water, where they lived together very
quietly for eight days. I put some duck-weed (_Lemna_) into the
glass to afford them shelter, and the females began to stretch
diagonal threads in a confused manner from it to the sides of the
glass about half way down. Each of the females afterwards fixed
a close bag to the edge of the glass, from which the water was
expelled by the air from the spinneret, and thus a cell was formed
capable of containing the whole animal. Here they remained quietly,
with their abdomens in their cells, and their bodies still plunged
in the water; and in a short time brimstone-colored bags of eggs
appeared in each cell, filling it about a fourth part. On the 7th
of July several young ones swam out from one of the bags. All this
time the old ones had nothing to eat, _and yet they never attacked
one another_, as other spiders would have been apt to do (Clerck,
Aranei Suecici, cap. viii.).”

“These spiders,” says De Geer, “spin in the water a cell of strong,
_closely woven, white silk_ in the form of half the shell of a
pigeon’s egg, or like a diving bell. This is sometimes left partly
above water, but at others is entirely submersed, and is always
attached to the objects near it by a great number of irregular
threads. It is closed all round, but has a large opening below,
which, however, I found closed on the 15th of December, and the
spider living quietly within, with her head downwards. I made a
rent in this cell, and expelled the air, upon which the spider
came out; yet though she appeared to have been laid up for three
months in her winter quarters, she greedily seized upon an insect
and sucked it. I also found that the male as well as the female
constructs a similar subaqueous cell, and during summer no less
than in winter (De Geer, Mém. des Insectes, vii. 312.).” “We have
recently kept one of these spiders,” says Mr. Rennie, “for several
months in a glass of water, where it built a cell half under water,
in which it laid its eggs.”

Thus it appears, that by the successive descents of the little water-spider under the impulsion of its instinct, produce effects in its subaqueous pavilion equivalent to those produced in the diving-bell, or diving helmet, by the successive strokes of the condensing air-pump of scientific man!

In the language of the book of Psalms, this insect “LAYETH THE BEAMS OF” her “CHAMBERS IN THE WATERS,” and there secures her subaqueous chambers in the manner described.

CLEANLINESS OF SPIDERS.--“When we look at the viscid material,” says Mr. Rennie, “with which spiders construct their lines and webs, and at the rough, hairy covering (with a few exceptions) of their bodies, we might conclude, that they would be always stuck over with fragments of the minute fibres which they produce. This, indeed, must often happen, did they not take careful precautions to avoid it; for we have observed that they seldom, if ever, leave a thread to float at random, except when they wish to form a bridge. When a spider drops along a line, for instance, in order to ascertain the strength of her web, or the nature of the place below her, she invariably, when she re-ascends, coils it up into a little ball, and throws it away. Her claws are admirably adapted for this purpose, as well as for walking along the lines, as may be readily seen by a magnifying glass. Fig. 13. Plate IV. shows the triple-clawed foot of a spider, magnified, the others being toothed like a comb, for gliding along the lines. This structure, however, unfits it to walk, as flies can do, upon any upright polished surface like glass; although the contrary[180] is erroneously asserted by the Abbé de la Pluche. Before she can do so, she is obliged to construct a ladder of ropes, as Mr. Blackwall remarks[181], by elevating her spinneret as high as she can, and laying down a step upon which she stands to form a second; and so on, as any one may try by placing a spider at the bottom of a very clean wine glass.

“The hairs of the legs, however, are always catching bits of web and particles of dust; but these are not suffered to remain long. Most people may have remarked that the house-fly is ever and anon brushing its feet upon one another to rub off the dust, though we have not seen it remarked in authors that spiders are equally assiduous in keeping themselves clean. They have, besides, a very efficient instrument in their mandibles or jaws, which, like their claws, are furnished with teeth; and a spider which appears to a careless observer as resting idly, in nine cases out of ten will be found _slowly combing her legs with her mandibles, beginning as high as possible on the thigh, and passing down to the claws_. The flue which she thus combs off is regularly tossed away.

“With respect to the house-spider (_A. domestica_), we are told in books, that ‘she from time to time clears away the dust from her web, and sweeps the whole by giving it a shake with her paw, so nicely proportioning the force of her blow, that she never breaks any thing[182].’ That spiders may be seen shaking their webs in this manner, we readily admit; though it is not, we imagine, to clear them of dust, but to ascertain whether they are sufficiently sound and strong.

“We recently witnessed a more laborious process of cleaning a web than merely shaking it. On coming down the Maine by the steam-boat from Frankfort, in August 1829, we observed the geometric-net of a conic spider (_Epeira conica_, WALCK.) on the framework of the deck, and as it was covered with flakes of soot from the smoke of the engine, we were surprised to see a spider at work on it; for, in order to be useful, this sort of net must be clean. Upon observing it a little closely, however, we perceived that she was not constructing a net, but dressing up an old one; though not, we must think, to save trouble, so much as an expenditure of material. Some of the lines she dexterously stripped of the flakes of soot adhering to them; but in the greater number, finding that she could not get them sufficiently clean, she broke them quite off, bundled them up, and tossed them over. We counted five of these packets of rubbish which she thus threw away, though there must have been many more, as it was some time before we discovered the manœuvre, the packets being so small as not to be readily perceived, except when placed between the eye and the light. When she had cleared off all the sooted lines, she began to replace them in the usual way; but the arrival of the boat at Mentz put an end to our observations.” Bloomfield, the poet, having observed the disappearance of these bits of ravelled web, says that he observed a garden spider moisten the pellets before swallowing them! Dr. Lister, as we have already seen, thought the spider retracted the threads within the abdomen.

[180] Spectacle de la Nature, i. 58.

[181] Linn. Trans. vol. xv.

[182] Spectacle de la Nature, i. p. 61.

“I could wish,” says Addison, in ‘The Spectator,’ “our Royal Society would compile a body of natural history, the best that could be gathered together from books and observations. If the several writers among them took each his particular species, and gave us a distinct account of its original, birth, and education; its policies, hostilities, and alliances; with the frame and texture of its inward and outward parts,--and particularly those which distinguish it from all other animals,--with their aptitudes for the state of being in which Providence has placed them; it would be one of the best services their studies could do mankind, and not a little redound to the glory of the All-wise Creator.”--‘Spectator,’ No. iii.

Although we do not consider Addison as a naturalist, in any of the usual meanings of the term, yet it would be no easy task, even for those who have devoted their undivided attention to the subject, to improve upon the admirable plan of study here laid down. It is, moreover, so especially applicable to the investigation of insects, that it may be more or less put in practice by any person who chooses, in whatever station or circumstances he happens to be placed. Nay, we will go farther; for since it agrees with experience and many recorded instances that individuals have been enabled to investigate and elucidate particular facts, who were quite unacquainted with systematic natural history, we hold it to be undeniable, that _any person of moderate penetration, though altogether unacquainted with what is called “Natural History_,” who will take the trouble to observe particular facts and endeavor to trace them to their causes, has every chance to be successful in adding to his own knowledge, and frequently in making discoveries of what was previously unknown. It is related of M. Pélissan, while a prisoner in the Bastille, that he tamed a spider by means of music. This in conjunction with Evelyn’s observations on hunting-spiders is strong proof of our position, and show that though books are often of high value to guide us in our observations, they are by no means indispensable to the study of nature, inasmuch as the varied scene of creation itself forms an inexhaustible book, which “even he who runneth may read.”

“It will be of the utmost importance, in the study here recommended, to bear in mind that an insect can never be found in any situation, nor make any movement, without some motive, originating in the instinct imparted to it by Providence. This principle alone, when it is made the basis of inquiry into such motives or instincts, will be found productive of many interesting discoveries, which, without it, might never be made. With this, indeed, exclusively in view, during an excursion, and with a little attention and perseverance, every walk--nay, every step--may lead to delightful and interesting knowledge.”--“INSECT ARCHITECTURE,” p. 219.

_Plate IV._

Spiders, with the processes of Spinning and Weaving.]