198 



AMERICAN SPIDERS AXD THEIR SPINNINGWORK. 



Till' (irli may 1>e said to, be 

 cniiiiiosed of ii scries of indi'- 

 peiidcnt rays or sectors, cacii 

 ray consisting of several si)i- 

 rally crossed radii, and the 

 wliole series united into an 

 orb by cross lines or spirals 

 like those which unite the ra- 

 dii. In the shifting of the 

 section lines above referred to, 

 tiiis separation of the orb in- 

 to inilependent rays is always 

 (juite evident. The spirals are 

 (■(ivrred witli viscid Ijcads, as 

 in most orl)webs. The radii 

 do not all pass to the hub or 

 centre, as do those of orbwebs 



Flu. 190. Side view of Ray spider's snare when drawn taut or generally, but COllVerge for the 

 bowed. Seen within a cavit.v. . , , i „ „£ 



most part upon the axes of 

 the rays as represented at Figs. 1S7, 188, 189. Thus at Fig 189 the 

 various radii of the several sectors converge consecutively upon the axes 

 i, ii, iii, iv. These axes themselves converge upon a single strong thread 

 or trapline, T, which is attached to some part of tlie surrounding surface 

 of rock, earth, or i)lant. 

 When the snare is flat or 

 relaxed, as was the case .^^.5^%, 

 with the one drawn at Fig. Wm^ 

 188, and as appears in Fig. 

 187, the trapline is often 

 about perjjcndicular to the 

 plane of the orb, having 

 the relative position of the 

 handle to the rays of an 

 ojjcn Japanese umbrella. 

 This, however, depends 

 somewhat upon the envi- 

 ronment ; a convenient 

 point for the attachment 

 of the trapline will cause 

 the animal to divert the 

 thread more or less from 

 the perpendicular. 



We may now suppose 



the spider placed as in Kk;. 101. Ila.v spider's snare when bowed. Viewed from behind. 



