THE S?IDF-R. 56 1 
iiial emits a poifon ; which, though liarmlefs to us, is 
capable of inftantly deftroying its prey. 
But all thefe arms of the fpider, formidable as they 
are, would prove infufficient for procuring him fubfift- 
ence, did he not add ftratagem to force. Every one is 
acquainted with his invention of fpreading a net for the 
fly,- an ififea which, without this artifice, mull for ever 
have e leaped him. The position of the fpider’s web is 
generally well chofen ; being placed either in the corners 
of rooms, the Tides of windows, or among the branches 
of trees, where flies are moll frequent and plenty. 
For the conftruaion of this delicate engine, Nature 
has fupplied thefe animals with a large portion of a glu- 
tinous fubftance, which Qie has granted them the power 
of fpinning into a thread fo delicate, that ninety of them 
twilled together are only equal in thicknefs to that of the 
common filk worm. Every thread of the common fpi- 
der’s web, though fcarcely vifible by the naked eye, is 
compofed of a valt number of flender filaments joined to- 
gether. The inlcruments of this delicate operation are 
five dugs or teats, with fmall orifices, capable of being 
contraaed or dilated, according to the finenefs of the in- 
tended thread. 
After the net has been thus formed,- the next care of 
its owner is to provide a proper retreat, from which he 
may furvey the whole, and obferve the fuccefs of his own 
artifice. Some threads being in contaa with his body, 
whenever the web is touched from without, he inftantly 
feels the motion, and accordingly prepares either for at- 
tack or defence. If the infeft invading his territories 
prove a fly, he immediately Tallies forth, and devours the 
devoted prey with all that ferocity which diftinguifhes 
Vol. HI. 4 B the 
