188 Mr. Black wall on the Construction, h)C. 



doing extensive injury to the frame-work of the snare. How this viscid 

 line is fabricated is at present unknovm. An examination of its struc- 

 ture, and of the apparatus by which it is produced would furnish interest- 

 ing employment for the microscope. 



In order to determine whether objects entangled in their toils are ani- 

 mate or inanimate, the geometric Spiders pull with their feet the radii 

 immediately in connection with that part of the snare in which they are 

 suspended, and suddenly letting go their hold, produce by this means a 

 vibratory motion in the net which seldom fails to excite to action such 

 insects as are ensnared. Guided by the struggles of her prey, the Spider 

 runs along the most contiguous radius to seize her victim, avoiding any 

 contact with the viscid line as much as possible, and drawing out after her 

 a thread attached to one of the lines near the centre of her net, which 

 serves to facilitate her return. 



I regret that I am unable to particularize those species of Spiders which 

 have been more especially the objects of the preceding observations and 

 experiments; but so little has been accomplished in this interesting 

 branch of zoology by British faunists since the time of Lister, that hitherto 

 all my attempts to determine some of them have proved ineffectual. 



Previously to giving my remarks publicity, I would gladly have availed 

 myself of the labours of our continental neighbours in this department of 

 natural history, but this would have been attended with considerable in- 

 convenience and much delay, and I am well informed that the works of 

 M. Walckenaer, who is regarded as the highest authority on this subject, 

 are out of print, and cannot be procured either in London or Paris.* A 

 book descriptive of British Spiders, if ably conducted, and accompanied 

 with accurately coloured engravings illustrative of species, would, I do 

 not doubt, be very favourably received by the naturalists of this kingdom. 

 That such a publication should still be a desideratum in the country which 

 has produced a Ray, a Lister and a Willughby is a humiliating reflection. 



♦ M, Walckenaer has commenced, in the Faune Franqaise, (a work now in 

 progress,) a history of the spiders which inhabit France. This will probably 

 include the greater number of the British species. — Ed. 



