416 FOOD OF INSECTS, 



never interfering. Another 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 spicier 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 

 dragged 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 

 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 ob- 

 jects towards which they were directed. He there- 

 fore infers that spiders have the power of shooting out 

 threads and directing them at pleasure towards a de- 

 termined point, judging of the distance and position of 

 the object by some sense of which we are ignorant. 

 Something like this manoeuvre I once myself witnessed 

 in a male of the small garden spider (Aranea reticulata). 

 It was standing midway on a long perpendicular fixed 

 thread, and an appearance caught my eye of what seemed 

 to be the emission of threads from its projected spinners. 

 I therefore moved my arm in the direction in which they 

 apparently proceeded, and, as I suspected, a floating 

 * An. vii. Vindemiaire. Translated in Phil. Mag. ii. 275, 



