ANIMAL AVOCATIONS 
245 
as rapidly as possible so as to prevent it filling 
up the trap and enabling its prey to reach the 
surface and regain its freedom. 
The spiders exhibit remarkable ingenuity 
in the construction of traps and snares, their 
beautiful silken structures being familiar to 
every one. Some of them, however, known as 
trap-door spiders, of which the British species 
may be taken as an example, construct tubular 
tunnels in the ground, wherein they lie in wait 
for their prey. This tunnel, which is lined 
with silk, extends below ground for a distance 
varying in length from nine to fifteen inches 
and has a diameter of about three-quarters 
of an inch. The nest is continued for a short 
distance above ground by a silken tube, 
strengthened with particles of sand or earth 
which render the outside of the extension less 
noticeable than it otherwise would be. This 
external portion, forming the snare, is attached 
to the surrounding herbage, and a number of 
threads are fixed to the inside and lead down 
to the bottom of the nest. 
Reposing within her domicile, the spider 
fastens the ends of these threads to her person 
and then awaits the approach of her prey. 
Should an insect happen to alight on the trap, 
the information is instantaneously communi¬ 
cated to the spider below by means of the 
