ENTOMOLOGY THE SPIDER. 89 



the silk formed by these insects is equally beautiful, strong, and glossy with that formed by 

 the bilk-wonii. 



. . . After a long and patient exainination M. Reaumur stated the following objectioiia 

 to Mr. Bon's plan for raibing spider-silk, vvhicli have ever since been regarded as insurmount' 

 able: 



1 . The natural fierceness of spiders renders them unfit to be bred together. On distrib- 

 uting four or five thousand of these insects into ci.-lls or companies of from fifty to one or two 

 hundred, it was found that the larger spiders quickly killed and ate the smaller, so that in a 

 short space of time the cells were depopidated, scarcely more than one or two being found 

 in each cell. 



2. The silk of the spider is inferior to tliat of the silk-wurni both in lustre and strength ; 

 and produces less in proportion, than can be made available t()r the pin-jioses of the manu- 

 facture. The lilauient of llie sjiidcr's Ittig can supjiorl a weight of only thirty-si.x grains, while 

 that of the silk-wona will sustain a weight of (jue hundred ;uid fifty grains. Thus four or 

 five threads of the spider must be brought together to equal cue threiid of the silk-worm, 

 iuid as it is impossible that tlicse should be applied so accurately over each other as not to 

 leave bttlo vacant spaces between them, the light is not equally ledected, and the lustre of 

 the material is consequently infenor to that in which a solid thread is used. 



3. A great disadvantage of the spider's silk is, that it cannot be wound otf the ball like that 

 of the silk-wonn, but must necessarily be carded. By this latter process, its evenness, which 

 condibutes so materially to its lustre, is destj-oycd. 



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 col- 

 lection of Hies sufficient to feed a lurge number of the spiders would not involve an amount 

 of expense fatal to the project iis a lucrative imdcrtakiug. 'J'he strength of the spiders' fila- 

 ment is, if anything, overstated by Reaumur. Deficiency of lustre arising from the carding 

 of the filaments is common to the spider-fabric and to spun silk ; this objection would, per- 

 haps, not be of very great weiglit but for the decisive calcidatlon by wliich Reaimiur showed 

 tlie comparative amount of production between the si)ider and the sUk-wonn. 



The largest cocoons weigh four, and the snuiller three grains each ; spider-bags do not 

 ■weigh above one grain each ; and, after being rle<u-ed of their dust, have lost t\\-o-tliirds of 

 this weight; therefore X\ic irork of twelve sp/drrn equals that ot only vnc nilk-irorm ; and a 

 pound of spider-silk wotdd require for its production 27,643 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 orcUuarily seen in gardens, &c. yielding not more than a 

 twelfth part of the silk of the others. The work of 280 of these woidd therefore not yield 

 more silk than the produce of one industi'ious silk-worm, audCG3,552 of them woidd flu'nish 

 only one pound of silk ! . . . 



Thk Ingknuity of Spiders. — Mr. Thomas Ewbank of New- York, in aletter to the Editor 

 of the Journal of IJie Franklin Institute, bearing date September 20tli, 1842, gives us the fol- 

 lowing interesting descrijjtion of the ingenuity of the spider: 



" The resources of the lower animals have often excited admiration, and though no comprehen- 

 Bive and systematic .series of observations have yet been made upon them, (?) the time is, I be- 

 lieve, not di.stant, wlicn the task will be undertaken — perhaps within the next century. But 

 whenever and by whomsoever accomplished, the mechiinism of animals will then form the sub- 

 ject 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 contri- 

 vances for cnsuuring 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 ran properly be brace<l ; and unless this be 

 done, light putt's or breezes of wind are apt to blow it into an entangled mass. Instead of being 

 spread out, like th(! sail of a ship, to tlu; wind, it would become clewed over the upper line, or 

 edge, like a sail when furled up. Xow how would a human engineer act under similar circum- 

 etaiices ? But ere the reader begins to rettect, (!) he should bear in mind dial it would not do to 

 brace the web by running rigging from it to mma 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 stru<;ture 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 winch we have referred, a spider has been known to descend from it to die ground by 

 means of a thread spun for the purpose, and after selecting a minute pebble, or piece of stone, lias 

 coiled the end of the thread round it. Having done this, the ingenious artist a.scended. and fix- 

 ing himself on the lower part of the web, hoisted up die pebble until it swung several inches clear 

 of the ground. The cord to which die weight was susi'cnded was then secured by additional 

 ones, running from it to different parts of the web, which thus ac([uired the requisite "tension, and 

 was allowed, at the same time, to yield to sudden puifs of wind without danger of being rent 

 asander. 



" 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 comer of my yard. The 

 upper edge v»as formed by a strong thread, secured at one end to a vine-leaf, and the other to a 

 (185) 



