432 PROCEEDINGS OF THE ACADEMY OP [1881. 



Ono other example ma_y be cited. At Cape May, by the Land- 

 ing, where pleasure boats used for sailing upon the inlet are 

 stored, there is an immense colony of Epiiiroids, chiefly Ej^eira 

 strix, E. vulgaris and E. domiciliorum (Hentz). Great numbers 

 of tiiese spiders had their lines strung between the opposite, 

 exterior walls of the boat-houses, which are built upon piles 

 driven into the water. These lines were about nine feet long, 

 stretched over the water at heights varying from one to ten feet. 

 Most of them passed from w^all to wall ; many were fastened at 

 one end upon piles and sticks driven here and there between the 

 houses. Even if one were to admit that Tetragnatha could carry 

 a free line over the smooth surface of an inland pool, it is past 

 belief that the above named Epeiras performed the same act x;pon 

 the rough w^aters of an inlet of the Atlantic Ocean. The only 

 reasonable conclusion is that bridge-lines were formed by air 

 currents, 



3' It was greatly desired that to the above cases of circum- 

 stantial proof, might be added actual observations of the use 

 for foundations of those lines stretched by air currents. Three 

 summer evenings were devoted to obtaining this result, without 

 complete success. On one evening the observer was interrupted 

 and c;dled off at the very critical loeriod of his observation; on 

 the other two evenings the wind was unfavorable. But some 

 valuable results were obtained, and the webs of three adult indi- 

 viduals of Epeira strix^ one male and two females, were selected, 

 the den or nest of each spider located, and the web entirely 

 destroyed, including the foundation lines. The latter precaution 

 was made necessary by the fact that orb-weavers had been noticed 

 to use the same foundation lines, for manj- days, for the erection 

 of their new webs. Young spiders had been seen on several occa- 

 sions to utilize the radii and foundations of abandoned webs of 

 adults, as the frame-lines of their small orbs. The great value 

 which maj^ 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. 



Two of the webs (one of the females) were so situated that the 

 prevailing air currents so carried the lines that they could not 

 possibly find an 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, which was more closely watched, was in motion 

 during the whole period, passing up and down, from limb to limb, 

 apparently desirous of fixing her orb in the former site, but com- 

 pletely confused and foiled. The site was one, moreover, which 

 would have allowed her to carry ai'ound a thread with compara- 

 tive ease, being a dead sapling that forked near the ground. The 

 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 



