414 FOOD OF INSECTS. 



That this therefore is one mode by which the geome- 

 tric spiders convey the main line of their nets between 

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

 on/y one is not so cleai*. If the position of the main hne 

 be thus determined by the accidental influence of the 

 wind, we might expect to see these nets arranged with 

 great irregularity, and crossing each other in every di- 

 rection ; 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. Anothei" objection too presents 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 ef- 

 fectually precluding the possibility of the spiders having 

 drasaed the lines from one to the other. Here there- 

 fore 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 Physique'', founded as he asserts on actual observa- 

 tion. He says that he saw a small spider, which he had 

 forced to suspend itself by its thread from the point of a 



scribes it as emitting numerous floating threads at the commencement 

 of its descent. That he is mistaken 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 ? 



"" An. vii. Vindeviiaire. Translated in Phil. Mag. ii. 275. 



