Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/523
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they have all three joints in each leg, but in Come the fore- moft pair are the longed, in others the hinder pair are fo, and in others fome of the intermediate pairs. The belly of the fpider is remarkably divided from the hSad and flioulders, fo as to adhere only by a thread : this is the cafe in all, except the two-eyed kinds, and in the different fpecies the body is varioufly 'painted. The appendages near the anus are very ohfervable, they ferve to (pin the threads out at. Among the many fpecies of thefe infects, fome are fmooth, others are hairy, and fome have a harder, fome a tenderer fkin. Ray's Hift. Infect, p. 12. Among the great number of fpecies of this infect, thefe are the principal diftinctions among thofe which have eight eyes. Some fpin webs for the catching of flies of a rounded fi- gure; thefe have all their eyes of the fame fize and figure ; they have four middle ones placed in a quadrangular figure, and the other four befide thefe, but (landing fomewbat ob- liquely. The firft pair of legs of thefe fpiders are always the longcft, the fecond pair are the longeft next to thefe, then the fourth pair, the third being much the fliorteft of all. Thefe fpiders are always fmooth, or nearly fo, and are elegantly figured on the buttocks. Of thefe fome always live in the center of the web, others have their habitation in a neighbouring corner. Of the firft of thefe forts we have five fpecies. I. The yellowifh ffidtr with white back and fides, and a white head with large pellucid black eyes. This is of a middle fize, and its legs are variegated with brown and white. The males in this fpecies are flendercr than the females, and of a more reddifh colour; and in both fexes the head and flioulders are fomewhat pellucid. 2. The hazel fp'uler with a crofs on its back, and tubercles on the belly. This fpecies fpins very large nets. 3. The (lender green and gold fpider with a long body. This is of a mid- dle fize, and its fore-legs are extremely-long. 4. The grey v/ood-Jpider with the body terminating in a three-cornered point. This is a fmall fpecies, but it fpins very large webs. Its belly is black.
Of the fecond kind of fpiders, which fpin round webs, and have their habitation at a corner of the web, not in its center, there are five principal fpecies. Thefe are, 1. the grey full-bodied fpider with various delineations on the back. This is a very large kind ; its flioulders are hoary, its legs thick, not long and fpotted. 2. The fmooth black croTs fpider with an oval body. This is of a middle fize, its legs are fliort and fpotted. It is very common among rufhes and water plants. 3. The yellow fpider with four great white fpots, and many fmall ones. 1 his is one of the largeft fpider:, and generally builds its habitation on the tops of plants. This is called by Mouffet, and fome others, the Cokhejler fpider : and there are two other fpecies which much refemble it ; the one diftinguiflied by having a chefnut- coloured head, and a black belly ; the other, by a large brown ftreak running from the flioulders to the tail. 4. The black fpider with figures like oak leaves upon its buttocks. It is a very large fpider. 5. The grey round-headed fpider with fo- liaceous lines on the buttocks, undulated at the edfres. This is a middle-fized one, and is common about houfes. Ray's Hift. Infect, p. 24..
Another genus of 'fpiders are diftinguiflied by their building conglobated webs ; thefe are all fmall, and have the fore- legs longeft of all, next thefe the hinder pair, and then the fecond, the third being the fmalleft of all. Of thefe there are fix principal kinds. 1. The black fmooth houfe-fpider. This is the largeft of this genus, and has ele- vated flioulders. 2. The white fpider with an oval body, furrounded with a fcarlet ring. 3. The brown fpider with a round body, ornamented with foliaceous figures. 4. The reddifh brown wood-fpider with a round body, marked with the figure of a ftar. 5. The fmall grey fpider with a black fpot upon its buttocks. And 6. the fmall livid fpider with denticulated figures on the rump. This ufually erects its conglobated nets on the top of the branches of furze bufhes.
A third genus of fpiders are diftinguiflied by the thicknefs and clofenefs of the webs ; fome of thefe inhabit the bottom, or funnel-end of their webs, others live near them, but not in them. Of the firft genus there are two remarkable fpecies.
1. The yellowifh hairy long-legged houk-fpider. This is of a middle fize, and its eyes are very black and fparklino-.
2. The great grey fpider with the appendices of the anus very remarkably prominent. This is a very large kind, and is of a livid colour.
Of the fecond kind of thefe, which live at a diftance from their webs, there are alfo two principal kinds. 1. The fmooth chefnut-coloured, or blackifll fpider with eleo-ant fnow-white fpots. This is of a middle fize, and has (on» and (lender legs. 2. The black fpider with white flioulders" and a denticulated white mark upon the back. This is of the middle fize. Its legs are hairy.
To thefe is to be added the cavefpider of Mouffet. This is a large black fpider with a very large fpot, of a deeper and more fhining black upon the flioulders. A fourth genus of fpiders, is diftinguiflied by the fmallnefs of the webs they build : thefe are, however, of a very clofc Suppl. Vol. II.
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texture, and the creature always lives within them. Of the Jpiders of tins kind there are three principal fpecies. ..The grey woolly fp.der with a broad black fpot on the belly 2. he plain livid, or yellowifh fpider. This is fometimeS of the one, and fometimes of the other of thefe colours, but never has any variegations. 3. The yellowifh cylindric- bodied fpider. This is a large fpider, and has fix eyes, 1 his has a long fenes, or chain of fpots on the back, and a yellowifh hne or ftreak on each fide. Ray's Hift. Infect, p. 30. See the articles Lupus and PhaiangiuM. 1 he fpider affords to the fagacious obferver, as wc-li with- out as with the affiftance of'glaffes, a great many extremely curious particulars. As the. fly (which is the fpider's natural prey) is an animal extremely cautious and nimble, and ufu- ally comes from above, it was neceffary the fpider fliould be furnifhed with a quick fight, and an ability of looking up- wards, forwards, and Tideways, at the fame time ; and the microfcrope (hews, that the number, flruflure, and difpofi- tion of its eyes, are wonderfully adapted to the fervihg all thefe purpofes. °
Moll fpiders have eight eyes : two on the top of the head or body, for there is no divifion between them, the fpider having no neck; thefe look diivjly upwards : there are two more in front, placed a little below thefe, and difcovering all that paffes forwards, and on each fide : a couple more, one whereof points fideways forward, and the other fide- 171- j ckward; fo that a can fa almoft quite round it. All kinds of fpiders have not, however, this exafl provifion ; for in fome we find ten, and in others only fix, or four. The eyes of the fpider are not pearled; and the i\e\A-fpiders, or long-legs, have no more than two eyes. Whatever be the number of the fpider's eyes, thev are however all immoveable and tranfparent, and are fituated'ina moftcuri- ous manner. The beft way of viewing them with the micro- fcope, 1S to cut off the legs and tail, and leave only the head for examination.
All fpiders have eight legs, which they employ in walkings and two fliorter, called arms, which they ufe in feizina their prey. All the legs are thickly befct with hairs ; each has fix joints, and ends with two hooked claws, which are ferrated on their infide; by means of thefe teeth, or ja«s in their claws, they feize very fad hold of any thing, and be- hind thefe there is a fort of fpur, which is perfcflly fmooth. Befide thefe, nature has allotted to this creature, for the feiz- ing its prey, a pair of (harp crooked claws, or forceps, iri the forepart of its head. Thefe (land horizontally, and when not exerted for ufe, are concealed in two cafes .con- trived for their reception, in which they fold like a clafp- knife, and there lie between two rows of teeth, which are likewife employed to hold faft the prey. Each of thefe claws, or pincers, has a fmall flit near its point, according to Lewenhoc-k, like that in a viper's tooth; through which he fuppofes that a poifonous juice is, in like manner, thrown out. But Dr. Mead, in his Effay on Poifons, diffents wholly from this opinion, having never been able, on repeated examinations, to difcover a*ny fuch opening, not even in the claws of the great Ameri- can fpider; which being above fifty times bigger than any of the European fpiders, would more eafily have difco- vered this opening, if nature had allotted any to this part of the animal. Befides, repeated obfervations alfo convinced him that nothing dropped out of the claws, which were al- ways dry, while the fpider bit any thing, but that a fliort white probofcis was, at the fame inftanF, thruft out of the mouth, which inftilled a liquor into the wound. And the fame author obferves, that the quantity of liquor, emitted by our common fpiders when they kill their prey, is vifibly fo great, and the wounding weapons fo minute, that they could contain but a very inconfiderable portion thereof, if it were to be difcharged that way. Baker's Microfcope, p. 196.
Spiders frequently caft their (kins, which may be found in their webs perfedly dry and tranfparent; and from fuch (kins the forceps, or claws, for they are always (lied with the (kins, may eafier be feparated, and examined with much greater exaflnefs, than in the common fpider while living. The fpider's manner of weaving its web is very wonderful. The creature has five little teats, or nipples, near the extre- mity of the tail ; from thefe there proceeds a gummy liquor, which adheres to every thing it is preffed againft, and be- ing drawn out, hardens inftantly in the air, and becomes a firing, or thread, ftrong enough to bear five or fix times the weight of the fpider's body. This thread is compofed of feveral finer ones, which are drawn out feparately, but unite together at two or three hairs breadth diftance from the creature's body. Thefe threads are finer or coarfer, ac- cording to the bignefs of the fpider that fpins them. Mr. Lewenhoek has computed, that a hundred of the (ingle threads of a full grown fpider are not equal to the diameter of the hair of his beard ; and confequently, if the threads and hair be both round, ten thoufand fuch threads are not bigger than fuch a hair. He calculates farther, that when young fpiders firft begin to fpin, four hundred of them are not larger than one which is of a full growth ; allowing 2 2 z z which.