NATURE'S CRAFTSMEN 



is insufficient to sustain the animal's weight, and it 

 cannot rise aloft. Other feints, perhaps, will follow, 

 which soon cover the posts and top rails with streaming 

 trial threads. 



In the mean time you have noted the spider's attitude 

 preceding flight. It faces the direction of the wind. 

 The abdomen is elevated about forty-five degrees, and 

 at the same time the eight legs, four on either side, are 

 straightened out, and the body thus raised above the 

 surface. At the apex of the abdomen and beneath it 

 are the spinnerets, covered with minute spinning-spools, 

 through which jets of liquid silk are forced from a multi- 

 tude of glands within the body. These harden at con- 

 tact with the air, and are held apart or combined at the 

 spider's will, by closing or outspreading the spinning 

 mammals. Keep the lens directed upon the spinnerets 

 of your little adventurer, A ray of several threads is 

 issuing, which, caught by the breeze, are drawn out and 

 upward six, ten, even twenty or more feet. Meanwhile, 

 the legs incline towards the breeze and the joints stiffen. 

 The foremost pair sink almost to the level of the post. 

 All the legs and the whole attitude show the muscular 

 strain of an animal resisting an uplifting force. 



Suddenly and simultaneously the eight claws are un- 

 loosened, and the spider mounts with a sharp bound 

 into the air, and floats above the meadow at a rate 

 more or less rapid, according to the velocity of the wind. 

 The threads have been drawn out so far that their 

 buoyancy has overcome the specific gravity of the 

 balloonist, and thus she is able to keep afloat. 



What is her manner of flight ? It may be a long time 

 before the observer shall find examples that give satis- 



186 



