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 ing the ends, many of which seemed to be purely tentative. At 
Move- ast a central point was taken, a short thread dropped therefrom 
ments. : 4 
and attached to one of these tentative lines. The confused net- 
work of cireumjacent 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 
Not Per- jines of orbwebs, and that spiders habitually make use of them 
apecad 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. 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 leayes 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. 
a i ee ell 
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