66 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



and mountains. (See Fig. 62.) This liabit 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 

 Cobweb j^g^ ]^-j^^g ^£ prodigous length, in which are arrested numbers 

 Bridfires x o o 



of Libelluke 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 Reunion 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- 

 ^. °^'^' weavers use the same foundation lines during many succes- 

 p " , sive 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 have 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 



s})iders 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 lier web in its former site, but conq)letely confused and foiled. The 

 site was one, moreover, which would have allowed her to carry around a 

 til read witli comparative ease, being a dead sapling that forked near the 

 ground. 



Tliis s])ider domiciled during the day on tlie ground, but had her orb 

 at tlie top of tlie forks, a lieight of six feet. Tlius the space to be 



' Aranoidop dos los Tslos La Ri'miirm. A-c. pa-av XTX. 



