198 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



The orb may be said to be 

 composed of a series of inde- 

 pendent rays or sectors, each 

 ray consisting of several spi- 

 rally crossed radii, and the 

 whole 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, 

 this separation of the orb in- 

 to independent rays is always 

 quite evident. The spirals are 

 covered with viscid beads, as 

 in most orbwebs. The radii 

 do not all, pass to the hub or 

 centre, as do those of orbwebs 



FIG. 190. Side view of Ray spider's snare when drawn taut or generally but Converge for the 

 bowed. Seen within a cavity. ' 



most part upon the axes of 



the rays as represented at Figs. 187, 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 the surrounding surface 

 of rock, earth, or plant. 

 When the snare is flat or 

 relaxed, as was the case 

 with the one drawn at Fig. 

 188, and as appears in Fig. 

 187, the trapline is often 

 about perpendicular to the 

 plane of the orb, having 

 the relative position of the 

 handle to the rays of an 

 open 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 FIG. 191. Bay spider's snare when bowed. Viewed from behind. 



