BY W. J. RAINBOW. 357 



her fangs therein, maintains her grasp until death ensues; there- 

 upon she envelopes the body in her thread and bears it to a quiet 

 spot, where she can devour in peace her spoil. This scene could 

 hardly be enacted by the largest Nejyhila on the smallest bird 

 known. Such, however, is my belief, and I feel certain that any 

 who will observe for themselves, and closely watch the subject, 

 will ultimately bear out my view of the case. It is, unhappily, 

 too often a fact that observers are in many instances prone to 

 hasty conclusions, and in recording these, render unsatisfactory, 

 or even useless, observations that might otherwise be of immense 

 value as data. 



The webs of these spiders are composed of two kinds of silk; 

 one yellow, exceedingly viscid, and elastic; the other white, dry, 

 and somewhat brittle. The latter is used in the construction of 

 the framework, guys, and radii, and the former the concentric 

 rings or spirals. The spirals are exceedingly numerous, and as a 

 rule somewhat less than one-third of an inch distant from each 

 other. Between every eight or ten of these circles there is a 

 white thread, which, however, does not form a complete circle, but 

 is looped up and returned in an opposite direction to a corres- 

 ponding point on the other side of the web. These white lines 

 are put in before the yellow ones are constructed, and doubtless 

 serve to strengthen the huge mesh. 



As the result of experiments with the American species, 

 Nephila pliimipes, Professor Wilder proved"^*" that these spiders 

 have the power of regulating the thickness of the thread voided, 

 and also that they can produce either yellow or white silk at will, 

 and he even succeeded in drawing off both by artificial means. The 

 Professor wound off silk from the species mentioned for an hour 

 and a quarter, at the rate of six feet per minute, making a total 

 of 450 feet, or 150 yards. This he afterwards removed from the 

 quill for the purpose of ascertaining^ its weight, and it was found 

 to be one-third of a grain. It was ascertained that it was impos- 

 sible to reel off more than 300 yards of silk from a spider at one 



* Proc. Bost. Nat. Hist. Vol. x. p. 200. 



