190 The Naturalist in La Plata. 



large colony are allowed to continue for a long 

 time in undisturbed possession of a ceiling, when 

 one has caught a fly he proceeds rapidly to throw a 

 covering of web over it, then, cutting it away, drops 

 it down and lets it hang suspended by a line at a 

 distance of two or three feet from the ceiling. The 

 other spiders arrive on the scene, and after a short 

 investigation retreat to their own webs, and when 

 the coast is clear our spider proceeds to draw up 

 the captive fly, which is by this time exhausted 

 with its struggles. 



Now, I have repeatedly remarked that all spiders, 

 when the shrill humming of an insect caught in a 

 web is heard near them, become agitated, like the 

 Pholcus, and will, in the same way, quit their own 

 webs and hurry to the point the sound proceeds 

 from. This fact convinced me many years ago that 

 spiders are attracted by the sound of musical in- 

 struments, such as violins, concertinas, guitars, &c., 

 simply because the sound produces the same effect 

 on them as the shrill buzzing of a captive fly. I 

 have frequently seen spiders come down walls or 

 from ceilings, attracted by the sound of a guitar, 

 softly played ; and by gently touching metal strings, 

 stretched on a piece of wood, I have succeeded in 

 attracting spiders on to the strings, within two or 

 three inches of my fingers ; and I always noticed 

 that the spiders seemed to be eagerly searching for 

 something which they evidently expected to find 

 there, moving about in an excited manner and look- 

 ing very hungry and fierce. I have no doubt that 

 Pelisson's historical spider in the Bastille came 

 down in a mood and with a manner just as ferocious 



