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 moodand with a manner just as ferocious 
