340 INSECT ARCHITECTURE. 



spiders, seeing that they are destitute of wingg, 

 transport themselves from tree to tree, across brooks, 

 and frequently through the air itself, without any ap- 

 parent 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 

 conjectural opinions, are, however, worthy of notice; 

 for, by unlearning error, we the more firmly esta- 

 blish 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 Svvammerdam,* by Leh- 

 mann the mineralogist, anc^. Kirby and Spence."]" 

 " The spider's thread," says Svvammerdam, " 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 (jEpeira 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 Uvo, 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, 



* Swammerdam, part i. p. 24. 

 + Intr, i. vol. p. 415= 



