ee ee a 
64 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
lines, settle upon a site between the forked twigs of a bush and carry her 
foundation lines around in the manner described. But, on the other hand, 
I am prepared to say that the air laid bridge lines are also used for the 
foundations or frames of orbs. The following are my reasons for this 
opinion :— 
1. First, the hours in the evening at which the greatest activity of web- 
weaving begins are those in which also begin the formation of the bridge 
lines. The latter action quite invariably precedes the former. 
2. Again, a study of the foundation lines of very many webs has given 
me almost conclusive evidence that they must haye been laid by the aid of 
air currents, For example, the webs of some species, as Acrosoma 
Webs mitrata, A. spinea, and A. rugosa, are frequently found strung be- 
Stretched | sen young trees separated by two or three yards of space. That 
between young P y y I 
Trees, these builders might have dropped to the ground, crept over the 
wood, grass, or dry leaves carrying the thread in the free, out- 
stretched claw is, perhaps, not impossible, but does not seem to me at all 
probable, although short spaces over smooth surfaces might be passed in 
this way. I once found an orb hung upon lines which stretched from the 
balustrade of a bridge that spans a deep glen in Fairmount Park, to the 
foliage of a tree that springs out of the glen at least twenty-five feet below 
the bridge. Unless the foundations of this orb were formed by line bridging 
the interspace of a yard or more, it must be inferred that the spider had 
dropped from the balustrade to the glen, crossed the interval to the trunk 
of the tree, ascended jt, and, having made a detour of nearly sixty feet to 
the point directly opposite that from which she started, all the while car- 
rying her line with her and keeping it free from entanglement, have drawn 
the line taut and so completed her foundation. Such a supposition could not 
well be entertained, and it is clear that a breeze carried the line across from 
the spider’s spinnerets. 
I haye noticed stronger examples of circumstantial evidence. Very many 
webs of Tetragnatha extensa and T. grallator have been seen spread upon 
bushes overhanging pools and streams of water; others were stretched be- 
tween separated water plants or from such plants to the shore, (See Fig. 60.) 
Either the foundation lines were borne by air currents, or the spiders must 
have crossed upon the water, carrying their lines. The latter supposition is 
not wholly untenable, but will hardly be raised by any one who has 
studied the spinning economy of the creature. 
One other example may be cited. At Atlantic City, by the boat- 
landing where pleasure boats used for sailing upon the Inlet are stored, 
there is (or was) an immense colony of Epeiroids, chiefly Epeira 
strix, E. sclopetaria, and E. benjamina (domiciliorum Hentz). 
During the summer months of 1880-81 great numbers of these 
spiders had their lines strung between the opposite exterior walls of the 
boat houses, which were built upon piles driven into the water, ‘These 
Orbs over 
W ater. 
