THE AKRONAUTIO OR BALLOONING HABIT. 259 



level of the post; and these especially, but indeed all the legs and the 

 entire attitude of the creature, presented the appearance of an animal 

 resisting with utmost force and tension of muscles the efPort of some su- 

 perior power to snatch it away. 



Suddenly and simultaneously the eight claws were unloosened, and tlie 

 spider mounted with a sharp bound into the air, and went careering away 



across the meadow, at a rate more or less rapid according to the 



velocity of the wind. The utmost care was used to determine 

 whether in this upward bound the volition of the spider had any further 

 agency than the simple unclasping of the feet from the post. Owing to 

 the extreme difficulty of such an observation, I cannot speak with absolute 

 confidence, but was able to satisfy my own mind that the aeronauts always 

 vaulted upward and clear of the post at the moment of releasing their 

 hold. I can hardly be mi.staken in the belief that this was .so in many 

 cases, at least. 



A similar action was frequently observed during the preliminary and 

 tentative movements in which the spiderlings indulged prior to the final 



flight. Something was noticed among them not unlike the frol- 

 Prohc- icsome pranks of kittens or lambs. One would rush up to an- 

 Spider- other, who thereupon would immediately change position, either 

 lings. t)y running or quickly vaulting to another part of the post. At 



times a leap would be made quite away from the post, but the 

 buoyancy of the thread which had been exuded being insufficient to over- 

 come the weight of the animal, instead of rising into the air, the creature 

 returned to th6 post or struck upon the adjoining rail. In these and sim- 

 ilar movements I was able to detect distinctly the vaulting action of the 

 spider, and the eye, being thus familiarized with the movement, was less 

 liable to be deceived in the more diflficult observation of the quick spring 

 at the time of the aerial flight. 



The posts and parts of railings adjoining were covered with threads 

 adhering to the wood and streaming out into the air. These were the 



result in part of the feints at flight just referred to, but were 

 Threads l""'*'y owing to another cause. The spiders, previous to flight 



or vaulting, attached themselves to the post in the manner com- 

 mon to most of their order. The apex of the abdomen was thrust down 

 upon the surface, and the liquid silk at the same time exuded from the 

 spinnerets was thus caused lo adhere thereto. As the creature moved away 

 the thread was run out into line, and gave tlie spider a firm attachment. 

 It is a question whether this anchorage is always made previous to flight, 

 and whether tlie thread is cut innnediately before the ascent. The obser- 

 vations made all pointed to an affirmative answer, but the matter was not 

 positively settled. 



The attempt was made to follow some of the aeronauts beyond the 

 point of ascent. The difficulty in getting the minute objects in position 



