118 A NATURALIST IN HIMALAYA 



filament escapes from the spider's spinnerets. Is it 

 drawn out by external traction or is it emitted by the 

 muscular effort of the spider ? I am inclined to believe 

 that the spider has no power to shoot forth its own 

 fragile thread. If we look to that large spider, the 

 Argyope, we see that the viscid spiral escapes from 

 the spinnerets only with great difficulty. The Argyope 

 certainly cannot shoot forth its viscid spiral. A defi- 

 nite traction is necessary to withdraw it. For once 

 this spider arrives at the construction of its viscid 

 spiral, its movements become more laboured ; it cannot 

 circle with the rapidity of other geometrical spiders. 

 At each attachment of the viscid spiral it has to grasp 

 the adhesive filament with its tarsus, slowly draw the 

 sticky line from its own spinnerets, sometimes transfer 

 it to the opposite tarsus to gain an additional purchase, 

 and not until it has with no little labour pulled from its 

 own abdomen a sufficient length of line is it able to 

 attach the spiral. 



Like the Argyope, so I think are the rest of the 

 Epeiridce, unable by their own internal force to thrust 

 out their silken lines. The thread must feel a gentle 

 strain before it can be drawn from the spinning-wheel. 

 I do not know of any time during the emission of the 

 silk when this strain is not clearly present. As the 

 spider circles from spoke to spoke it strains on its last 

 attachment ; as it suddenly drops suspended on a fila- 

 ment the strain becomes its own weight ; as it gives its 

 first line to the breeze the strain is on the tuft of finest 

 fibrils that catch the moving air ; and in the beautiful 

 Argyope the strain is often the traction exerted on the 

 line by the spider's own legs. During the emission of 

 the line, therefore, there is ajways some tension pro- 



