LAND SPIDERS* 237 



portion to the spokes, and is adhesive in its character, 

 as passing flies know to their cost. Its adhesiveness is 

 due to little globules of gummy matter, which are 

 arranged upon the thread like beads on a string. These 

 little gum-beads can be rubbed off by careful manipulation, 

 and then the thread is found to be no longer adhesive. 

 A tolerably powerful pocket-lens will show these 

 beads. 



On hot, dry, windy days, dust is apt to adhere to the 

 gum, and so impair its adhesiveness. The spider is 

 well aware of this fact, and is constantly employed in 

 clearing the web from dust, using for this purpose the 

 comb-like bristles of the feet. 



The mode in which the spider constructs its web is 

 sufficiently curious. It travels round and round, 

 trailing behind it a thread, which is guided by one of 

 the hind legs. As it passes each spoke, it hitches the 

 spiral thread upon it with a sharp regular movement, 

 which much resembles the quick turn of a knitter's 

 forefinger. The thread is always held diagonally 

 across the web, and when it is attached to the spoke, 

 its own elasticity draws it straight. 



Were it not for the elasticity of the silk, the spider 

 could not maintain its web, nor get its living. The web 

 is attached to leaves and twigs, which are swayed about 

 by every breath of air, so that they would tear the web 

 to pieces were it not so exceedingly elastic. 



Even the struggling of a moderately large fly would 

 tear the web if its material were not elastic. But, as it 



