344 INSECT ARCHITECTURE. 



ticular place."* Without pretending to have ob- 

 served this, Swammerdam says, " I can easily com- 

 prehend how spiders, without giving themselves any 

 motion, may, by only compressing their anus, spin 

 out a thread, which being driven by the wind, may 

 serve to waft them from one place to another."-} - 

 Others, proceeding upon a similar notion, give a 

 rather different account of the matter. " The spider," 

 says Bingley, " fixes one end of a thread to the place 

 where she stands, and then with her hind paws draws 

 out several other threads from the nipples, which, 

 being lengthened out and driven by the wind to some 

 neighbouring tree or other object, are by their natu- 

 ral clamminess fixed to it." J 



Observation gives some plausibility to the latter 

 opinion, as the spider always actively uses her legs, 

 though not to draw out the thread, but to ascertain 

 whether it has caught upon any object. The notion 

 of her pressing the spinneret with her feet must be 

 a mere fancy ; at least it is not countenanced by any- 

 thing which we have observed. 



4. An opinion much more recondite is mentioned, 

 if it was not started, by M. D'Isjonval, that the float- 

 ing of the spider's thread is electrical. " Frogs, cats, 

 and other animals," he says, " are affected by natural 

 electricity, and feel the change of weather ; but no 

 other animal more than myself and my spiders." 

 During wet and windy weather he accordingly found 

 that they spun very short lines, " but when a spider 

 spins a long thread, there is a certainty of fine wea- 

 ther for at least ten or twelve days afterwards. "§ A 

 periodical writer, who signs himself Carolan,|| fancies 

 that in darting out her thread the spider emits a 



* Spectacle de la Nature, vol. i. f Book of Nature, part i. p. 28. 



I Animal Biography, vol. iii. p. 475, 3rd edition. 



§ Brez, Flore des Insectophilcs. Notes, Supp. p. 134. 



Thompson s Ann. of Philosophy, vol. iii. p. 306. 



