SPIDERS. 367 



rough, hairy covering (with a few exceptions) of 

 their bodies, we might concUide 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 caretiil 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 inva- 

 riably, 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. 



Triph-clawed foot of u Spiler, magnifiid. 



There are three claws, one of which acts as a 

 thumb, 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* 

 is erroneously asserted by the Abbe de la Pluche. 

 Before she can do so, she is obliged to construct a 

 ladder of ropes, as Mr Blackwall remarks,! by ele- 

 vating her spinneret as high as she can, and laying 



' Spectacle de la Nature, i. 58. t Linn. Trans, vol. xv. 



