70 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



During the intervals of the attempts above described, and, indeed, pre- 

 ceding them, our Furrow spider passed back and forth along the branch- 

 ing twigs, leaving behind him trailed threads or lines connect- 

 Tentative j n g fa e ends, many of which seemed to be purely tentative. At 



"TV/T (~\ TT fi _ 



ments ^ as ^ a cen ^ ra ^ P om t was taken, a short thread dropped therefrom 



and attached to one of these tentative lines. The confused net- 

 work of circumjacent lines was gathered together in a little flossy ball at 

 the point of union, which was now made the centre of the orb, the first 

 dropline and two divisions of the cross line constituting the three original 

 radii. From these the spider proceeded to lay in the radii and complete 

 an orb. The time occupied in constructing the web proper was half an 

 hour, while the work of prospecting for and obtaining a foundation con- 

 sumed more than an hour. Even then the orb was very irregular, and 

 showed decided traces of the want of the usual well and orderly laid 

 foundations. An examination of a number of web sites which I had 

 marked upon the same grounds, showed that in every case where the sur- 

 roundings had allowed an easy and good entanglement by the wind, the 

 spiders had made webs at an early hour, and with straight and regular 

 foundations. 



I feel justified in saying that the above observations which might be 

 indefinitely multiplied, are sufficient warrant for the belief that air currents 



have a large part in placing the original framework or foundation 

 STotPer- j mes O f orb webs, and that spiders habitually make use of them 



for that purpose. I doubt, however, whether there is anything 

 trolled. like a deliberate purpose in any case to connect the point of 



occupancy with any special opposite point. The spider seems to 

 act in the matter very much at hap hazard, but with a general knowledge 

 that such behavior would somewhere secure available attachments. Many 

 of her bridge lines are evidently tentative and chiefly at the mercy of the 

 breeze, although some observations indicated a limited control of the thread 

 by manipulation. 



This use of air currents is depended very much upon the- site chosen, 

 the condition of the wind, the abundance of prey, etc. Webs built in large 

 open spaces are perhaps always laid out by bridge lines, at least as to the 

 first and principal line or lines. In more contracted sites the frame lines 

 are generally carried around, and often a foundation is the result of both 

 methods. 1 The above observations have been fully confirmed by the 

 behavior of spiders colonized upon the vines and shrubbery in my manse 

 yard. The securing of one principal line is the important desideratum. 

 This obtained, the remainder is generally easy. In carrying around a frame 

 line the largest spider will move with great deftness over the leaves and 



1 Blackwall, Constr. Nets Geom. Spiders, page 186, and Kirby and Spence, Introduction, i., 

 page 413, knew that spiders could form foundation lines by means of air currents. 



