348 



FOOD OF INSECTS. 



in the air, some one of which attaching itself to a neighbour- 

 ing object, furnishes a bridge for its escape. It was clear 

 that if this mode is pursued by the geometric spiders, it would 

 go considerably towards furnishing a solution of the difficulty 

 in question. I accordingly placed the large diadem spider 

 {Epeira Diadema) upon a stick about a foot long, set upright 

 in a vessel containing water. After fastening its thread (as 

 all spiders do before they move) at the top of the stick, it 

 crept down the side until it felt the water with its fore feet, 

 which seem to serve as antennae : it then immediately swung 

 itself from the stick (which was slightly bent) and climbed 

 up by the thread to the top. This it repeated perhaps a 

 score times, sometimes creeping down a different part of the 

 stick, but more frequently down the very side it had so often 

 traversed in vain. Wearied with this sameness in its oper- 

 ations, I left the room for some hours. On my return I was 

 surprised to find my prisoner escaped, and not a little pleased 

 to discover, on further examination, a thread extended from 

 the top of the stick to a cabinet seven or eight inches distant, 

 which thread had doubtless served as its bridge. Eager to 

 witness the process by which the line was constructed, I re- 

 placed the spider in its former position. After frequently 

 creeping down and mounting up again as before, at length it 

 let itself drop from the top of the stick, not as before 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 dis- 

 tinctly 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 approaching a pencil to the loose 

 end of this line, it did not adhere from mere contact. I 

 therefore twisted it once or twice round the pencil, and then 

 drew it tight. The spider, which had previously climbed to 

 the top of the stick, immediately pulled at it with one of its 

 feet, and, finding it sufficiently tense, crept along it, strength- 



