66 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
and mountains. (See Fig. 62.) This habit is not limited to American 
spiders. Vinson! says that in Madagascar Epeira (Nephila) tuberculosa 
throws from one bank to the other of streams of considerable size 
her lines of prodigous length, in which are arrested numbers 
of Libellule and large Agrions. He had observed this phenom- 
enon upon running streams of forest interiors. One might call them, in 
truth, aerial bridges. In the island of Réunion it is to the wrinkled trunks 
of the huge Pandanus that the gigantic Orbweavers attach their long silken 
lines, and stretch them from one tree to another at a distance of many 
metres. 
3. I have greatly desired, but heretofore without complete success, that 
to the above cases of circumstantial evidence might be added actual ob- 
servations of the use for foundations of lines stretched by air currents. 
Three summer evenings were once entirely devoted to endeavors to obtain 
this result. On one evening I was interrupted and called off at a very 
critical period of my observation; on the two other evenings the wind was 
unfavorable; but some valuable results were obtained. ‘The webs of three 
adult individuals of Epeira strix, one male and two females, were selected, 
the den or nest of each spider located, and the web entirely destroyed. 
The latter precaution was made necessary by the fact that Orb- 
Old Foun- weavers use the same foundation lines during many succes- 
dations s - . 
Prasorved =" days for the erection of their new webs. The great value 
which may attach to these old foundations appeared strikingly in 
subsequent studies, and also the difficulty-if not impossibility of procuring 
suitable foundations for the webs of large spiders without the aid of the 
wind. In fact, a good foundation frame is a “good property,” and it is ac- 
cordingly treasured and used as long as it remains. I haye noted many 
cases of snares continuing on the same site as long as the foundation lines 
endure. Their destruction is generally followed by a shifting of position, 
Two of the above webs (one of the females) were so situated that the 
prevailing air currents carried the lines in such wise that they could not 
possibly find entanglement. In consequence neither of these 
spiders succeeded, during two entire evenings up to half-past ten 
o'clock, in making a web. ‘They frequently attempted it in vain. One 
spider that was more closely watched, was in motion during the whole 
period, passing up and down, from limb to limb, apparently desirous of 
fixing her web in its former site, but completely confused and foiled. ‘The 
site was one, moreover, which would have allowed her to carry around a 
thread with comparative ease, being a dead sapling that forked near the 
ground. 
This spider domiciled during the day on the ground, but had her orb 
at the top of the forks, a height of six feet. Thus the space to be 
Cobweb 
Bridges. 
Failures. 
1 Araneides des les Isles La Réunion, &e., page XTX. 
