370 Insect Architecture. 



cord. The preceding figure exhibits this ingenious contri- 

 vance. 



Those who may be curious to examine this contrivance 

 will see it best when the line is attached to any black object, 

 for the threads, being whitish, are, in other cases, not so 

 easily perceived. 



SHOOTING OF THE LINES. 



It has long been considered a curious though a difficult 

 investigation, to determine in what manner spiders, seeing 

 that they are destitute of wings, transport themselves from 

 tree to tree, across brooks, and frequently through the air / 

 itself, without any apparent starting point. On looking into 

 the authors who have treated upon this subject, it is surpris- 

 ing how little there is to be met with that is new, even in 

 the most recent. Their conclusions, or rather their conjec- 

 tural opinions, are, however, worthy of notice ; for by un- 

 learning error, we the more firmly establish truth. 



1. One of the earliest notions upon this subject is that of 

 Blancanus, the commentator on Aristotle, which is partly 

 adopted by Kedi, by Henricus Eegius of Utrecht, by Swam- 

 merdam,* by Lehmann, and by Kirby and Spence.f " The 

 spider's thread," says Swammerdam, " is generally made up 

 of two or more parts, and after descending by such a thread, 

 it ascends by one only, and is thus enabled to waft itself from 

 one height or tree to another, even across running waters ; 

 the thread it leaves loose behind it being driven about by 

 the wind, and so fixed to some other body." " I placed," 

 says Kirby, " the large garden spider (Epeira diadema) upon 

 a stick about a foot long, set upright in a vessel containing 



water It let itself drop, not by a single thread, 



but by two, each distant from the other about the twelfth of 

 an inch, guided, as usual, by one of its hind feet, and one 

 apparently smaller than the other. When it had suffered 

 itself to descend nearly to the surface of the water, it stopped 

 short, and by some means, which I could not distinctly see, 

 broke off, close to the spinners, the smallest thread, which 

 * Swammerdam, part i. p. 24. f Intr., vol. i. p. 415. 



