FOOD OF INSECTS. 



347 



In the above description, which is from my own observa- 

 tions, I have supposed the spider to fix the first and main line 

 of her net to points from one of which she could readily climb 

 to the other, dragging it after her ; and many of these nets 

 are placed in situations where this is very practicable. They 

 are frequently, however, stretched in places where it is quite 

 impossible for the spider thus to convey her main line — 

 between the branches of lofty trees having no connection 

 with each other; between two distinct and elevated build- 

 ings ; and even between plants growing in water. Here then 

 a difficulty occurs. How does the spider contrive to extend 

 her main line, which is often many feet in length, across in- 

 accessible openings of this description? 



With the view of deciding this question, to which I could 

 find no very satisfactory answer in books, I made an experi- 

 ment, for the idea of which I am indebted to a similar one 

 recorded by Mr. Knight ^, who informs us that if a spider 

 be placed upon an vipright stick having its bottom immersed 

 in water, it Avill, after trying in vain all other modes of es- 

 cape, dart out numerous fine threads so light as to float 



metric spidei's, as some of them do not entirely surround the radii of their nets 

 with concentric cii'cles, but leave one radius free, which serves as a sort of ladder 

 for access to the net ; and as in general they do not bite away the small cotton- 

 like tuft that unites the radii in the centre, nor place themselves there to watch 

 their prey, but retire under a leaf or other shelter, and there construct a cell in 

 which the spider remains concealed till the vibrations of a strong line of com- 

 munication, composed of several united threads, which she has spun from the 

 centre of the net to her cell, inform her of the capture of a fly, to which she then 

 rushes along this bridge. This criticism as to the too extensive generalisation of 

 the procedures of the garden spider above described is perfectly just, as my own 

 observations since the publication of the last edition of this work, but long before 

 I had seen Mr. Blackwall's paper, had shown me. My excuse must be that the 

 observations above recorded (which are left precisely as originally written about 

 the year 1812), having been made on the spur of the occasion in my garden at Dry- 

 pool near Hull, when to my surprise I could not find in books any intelligible ac- 

 count of the way in which the geometric spiders construct their nets, were necessarily 

 confined to the common garden sjsecies alone found there, and my attention 

 liaving been subsequently fully occupied in other directions, it did not occur to 

 me that probably the operations of other species might differ from those I had 

 witnessed. These variations, however, do not affect the accuracy of the descrip- 

 tion above given of the procedures of the species referred to, one of the com- 

 monest of the tribe, which description also, except in the two particulars above 

 stated, is generally applicable to the whole geometric race, and has been in great 

 part adopted by Mr. Blackwall in his more full detail of their operations. 

 1 Treatise, on the Apple and Pear, p. 97. 



