174 Journal New York Entomological Society, f^'o'- xxii. 



nando Noronha. Nevertheless, even a four months' stay in the icy 

 fiords of South Georgia Island, in latitude 55° South, did not elimi- 

 nate the spiders, for they became active again as soon as we en- 

 countered warm weather on the return voyage. 



The curious "whirling" defence of this species of spider is well 

 known. When disturbed the animal rotates its body upon its legs, 

 keeping the tips of the tarsi close together upon the web, while the 

 legs are pulled out straight by centrifugal force and the rapid circling 

 conceals the spider in a blur. 



During the last week of August, 1912, when the vessel had been 

 about two months out of port, I made a series of experiments upon the 

 spiders in the cabin in order to determine their reaction to stimuli of 

 touch, wind, odor, light, etc., and the duration and reiteration of the 

 "whirling defense." The averages of the reactions are as follows: 

 I. The whirling response was made to tactile stimuli, that is when- 

 ever the body of the spider was actually touched with a hair, how- 

 ever lightly, or the web shaken. 



2. The whirling response was not made to violent blowing of the 

 breath on the spider, to the close juxtaposition of a finger or stick, 

 to the odor of strong alcohol, nor to sunlight flashed from a mirror. 

 If these stimuli were continued, however, the spider would finally 

 drop from the web and retreat to a hiding place. 



3. In the whirling response the first reaction to the touch stimulus 

 was of brief duration, the spider soon slowing down, and coming 

 to rest within 15 seconds. 



4. The second and third responses were increasingly violent and 

 of longer duration. 



5. The third or fourth response (usually the latter), marked the 

 maximum, the whirling lasting from 2 minutes and 15 seconds to 3 

 minutes. 



6. After the third or fourth stimulus the jerky, feeble response 

 indicated fatigue. The whirlings became shorter and slower, and dis- 

 turbance continued seven or eight times always resulted in the spider 

 dropping from the web and retreating. — Robert Cushman Murphy. 



