THE ARSrATURE OF ORBWEBS : VISCID SPIRALS. 93 



ningwork at the point where it was abandoned and finished it in the usual 

 manner, so that the orb jjresented the appearance shown at Fig. 87. The 

 spirals were not only greatly deltated by the action of the rain, the crossed 

 lines being merged and twisted together at the middle jiart, but the beads 

 upon them had been taken up by the raindrops, a number united into one, 

 so that instead of the ordinary condition of a vast number of minute beads 



sju'ead entirely along the line there appeared a much smaller 

 Interrupt- j-^^jj-j-^ljgj. ^^ beads of larger size, that distinctly showed to the 

 ■ p- naked eye. Then the unexplained mystery of the Orchard spider's 

 ished. jieculiar snare flashed upon my mind ! At once the mystery 



was solved, and that in a most simple and natural way. The 

 peculiar appearance of the orb was simply the result of the spiders resum- 

 ing arrested work upon the spirals after the same had been abandoned on 

 account of a shower, and which in the meantime had been twisted and 

 deltated by the action of the elements, and the size and grouping of the 

 beads changed. As the renewed work was spun in, in the ordinary way, 

 both as to the position of the lines and the size of the beads, the con- 

 trast with the larger beads and the more widely separated spirals of the 

 earlier belt was very great. It was not tlie first time that I learned the 

 valuable lesson that natural jihenomena are often to be explained by the 

 simplest and ordinary causes, while we are vainly speculating and philoso- 

 l)hizing over some supposed occult and mysterious reason. 



III. 



Mr. Blackwall remarks that "the estimate of the number of viscid 



globules distributed on an elastic spiral line in a net of Epeira apoclisa of 



a medium size will convey some idea of the elaborate ojierations 



Number ^^ ^|^^^ Epeiroid* in the construction of their snares." ^ This quo- 



of S63jQ.S 



tation evidently indicates that Blackwall supposed the viscid glob- 

 ules to be the result of " elaborate operations " on the part of the Orbweaver, in 

 other words, that they are formed by direct and intentional action. This 



has been the well nigh universal belief. But in the light of the 

 An Error ^^.^^^ mode above recorded, it is necessary to diminish by so much 



the credit heretofore bestowed upon this child of Arachne. 



It would be an extremely laborious, if not impossible task, to ascertain 



the exact number of beads upon an orbweb, but I reached a near enough 



approximation by the following process : A sector of a snare was taken, that 



is, a complete section extending from the hub to the circumference between two 



radii, and the number of beads thereon was carefully counted. 



Number- r^j^-^ gg^^^^j. ^^s then measured and the superficial area calculated. 



' The superficial area of the entire beaded space having been obtained 



in like manner, the number of beads ui)on the whole web was readily calcu- 



1 Jour. Linn. Soc, 1829, Vol. XVI., page 477, and Ann. Mag. Nat. Hist., Vol. XV., page 239. 



