BRITISH BUTTERFLIES 



the light strikes it in certain directions ? Incredible 

 as it may seem, this thread is not simple, but consists, 

 in reality, of quite a large number of filaments, being, 

 in fact, somewhat of the nature of a ribbon, and in- 

 tended to offer as considerable a resistance to the breeze 

 as is possible. Although you cannot actually con- 

 firm it in the present instance, you may take my word 

 for it that this ribbon is being paid out with wonderful 

 rapidity. 



It was formerly believed, chiefly by reason of the fact 

 that these lines are often cast on days when there is no 

 perceptible motion in the air, that the spider could 

 project them where and when it chose : but experi- 

 ments made with air rendered perfectly stationary by 

 scientific means have demonstrated the fallacy of this 

 supposition, and have shown that an air current is 

 absolutely necessary. It is, however, manifest that a 

 breeze quite inappreciable to the human senses would 

 be sufficient to carry a ribbon whose delicacy is such that 

 spun silk, by comparison, is course and heavy. 



The thread is formed from a viscous liquid, secreted 

 by special glands in the body of the spider, which liquid, 

 when brought into contact with the air 'in the finely 

 divided state exhibited in these filaments, hardens 

 immediately, and forms one of the strongest cables, 

 in proportion to its size, that Nature or man can 

 produce. Notice how tenaciously the little creature 



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