340 INSECT ARCHITECTUltE. 



port themselves from tree to tree, across brooks, and 

 frequently through the air itself, without any appa- 

 rent starting point. On looking into the authors who 

 have treated upon this subject, it is surprising 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 

 unlearning error, we the more finmly establish truth. 

 1. One of the earliest notions upon this subject 

 is that of Blancanus, the commentator on Aristotle, 

 which is partly adopted by Redi, by Henricus Regius 

 of Utrecht, by Swammerdam,* 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 wa- 

 ter 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, 

 still adhering by the other end to the top of the 

 stick, floated in the air, and was so light as to be 

 carried about by the slightest breath. On ap- 

 proaching a pencil to the loose end of this line, it 

 did not adhere from mere contact. I, therefore, 



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



