231 



neighl)oring crack or corner, from wliicli tliey rush to seize tlieir 

 prey, and sometimes there is a funnel-shaped tube leading to their 

 nest. But these spiders differ from the true funnel-web weavers in 

 running" back downwards on the lower side of their webs. 



The Orb Weavp:ks. 



The spider webs that most often excite admiration are those in 

 which the supporting threads radiate from a center like the spokes of 

 a wheel, and l)ear a spiral thread. 

 Such webs are known as orb-webs; 

 and the family of spiders that 

 make them, The Orb Weavers. 



P^ew if any of the structures 

 built by lower animals are more 

 wonderful than these webs ; but 

 they are so common that they are 

 often considered hardly worthy 

 of notice. If they occurred only 

 in some remote corner of the 

 earth, every one would read of 

 them with interest. 



The webs or nets of the dif- 

 ferent species of orb weavers 

 differ in the details of their 



115. - Nearly completed orh-ioeh. 



structure; but the general plan is quite similar. There is first a 

 framework of, supporting lines. The outer part of this framework 

 is irregular, depending upon the position of the objects to whicli 

 the net is attached ; but the central part is very regular, and con- 

 sists of a number of lines radiating from the center of the net 

 (Fig. 115). All of these supporting lines are dry and inelastic. 

 Touch them with your pencil and you find that they neither stretch 

 nor adhere to it. Upon these radiating lines there is fastened in a 

 very regular manner a thread which is sticky and elastic. This will 

 adhere to your pencil, and will stretch several times its normal 

 length before breaking. Usually this sticky thread is fastened to 

 the radiating lines so as to form a spiral ; but a few species make 



331 



