FOOD OF INSECTS. 349 



ening it as it proceeded by another thread, and thus reached 

 the pencil.^ 



That this therefore is one mode by which the geometric 

 spiders convey the main line of their nets between distant 

 objects, there can be no doubt, but that it is the only one is 

 not so clear. If the position of the main line be thus deter- 

 mined by the accidental influence of the wind, we might ex- 

 pect to see these nets arranged with great irregularity, and 

 crossing each other in every direction; yet it is the fact, that 

 however closely crowded they may be, they constantly appear 

 to be placed not by accident but design, commonly running 

 parallel with each other at right angles with the points of 

 support, and never interfering. Another objection too pre- 

 sents itself. From the experiment related, it is clear that 

 the main line of the net can never be longer than the height 

 of the object from which the spider dropped in forming it. 

 But it is no uncommon thing to see nets in which these lines 

 are a yard or two long fastened to twigs of grass not a foot 

 in height, and yet separated by obstacles effectually precluding 

 the possibility of the spiders having dragged the lines from 

 oner to the other. Here, therefore, some other process must 

 have been used. 



Both these difficulties would be removed by adopting the 

 explanation of an anonymous author in the Journal de Phy- 

 sique ^ founded, as he asserts, on actual observation. He says 

 that he saw a small spider, which he had forced to suspend 

 itself by its thread from the point of a feather, shoot out 

 obliquely in opposite directions other smaller threads, which 

 attached themselves in the still air of a room, without any 

 influence of the wind, to the objects towards which they were 



1 Some time after making this experiment I stumbled upon a passage in Redi 

 (Z)e Insectis, p. 119.), from which it appears that Blancanus, in his Commentaries 

 upon Aristotle, has related a series of observations which led him to precisely the 

 same result. Lehmann, too, in a paper in the Transactions of the Society of 

 Naturalists at Berlin (translated in the Philosophical Magazine, xi. 323.) has 

 given an explanation somewhat similar of the operations of this very spider, but 

 1 am inclined to think erroneous in some particulars. He describes it as emitting 

 numerous floating threads at the commencement of its descent. That he is mis- 

 taken in supposing these threads to be more than one, is proved by the fact which 

 I have observed — that even that one sometimes breaks by the weight of the 

 spider. How then could an insect almost as big as a gooseberry be supported 

 by a line of the tenuity here attributed to it ? 



2 An. vii. Vindemiaire. Translated in Phil. Mag. ii. 275. 



