92 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



FIG. 87. Effect of rain upon an orb. The open marginal space was 

 spun before, the remainder after, a shower. 



being just two to one in 

 both cases. This regu- 

 larity of proportion add- 

 ed to my perplexity in 

 seeking an explanation 

 for the appearance. Why 

 should the spider have 

 made such a peculiar 

 division in her spiral 

 space? Was I on the 

 track of some new and in- 

 teresting departure from 

 the fixed habit of this 

 species? The snares were 

 figured and described, 

 and for a number of 

 years I sought in vain 

 for an explanation of the 

 peculiarity, which, how- 

 ever, I saw but once again, and that in an Orchard spider's web. 



At last I found the explanation. On the honeysuckle and ampelopsis 

 vines growing in considerable profusion in my manse premises, I had colon- 

 ized a number of Orbweavers, including several examples of Ar- 

 giope cophinaria. One morning in September, just after a warm 

 shower, while going the rounds of my colonists, I observed on 

 several orbs that a series of spiral lines had been spun from the margin 

 inward, covering about one-half the ordinary spiral space. No other beaded 

 spirals appeared; and looking a little more carefully I observed that those 

 upon the web were all greatly deltated and much more widely separated 

 than usual. In fact, I came to the conclusion that the Argiopes had been 

 engaged upon this part of their snare when overtaken by the shower ; that 

 they had abandoned their work, fled 

 to their refuge, and in the meantime 

 the beating raindrops had twisted the 

 spiral lines already spun, until they 

 presented the appearance described, 

 and which is shown at Fig. 88. 



An hour thereafter I left my study 

 to reinspect the colonists upon the 

 vines. The rain had ceased ; the sun 

 was shining pleasantly, and I was sur- 

 prised to observe that the partly completed webs had now been finished. 

 But instead of cutting away the portions originally wrought in, and wliiHi 

 had been partially disabled by the rain, the spiders had taken up their spin- 



Effect of 

 Eain. 



FIG. 88. Section of Argiope's orb interrupted by a 

 shower. 



