ON ARACHNIDA. 
465 
the side of the most elevated edge of the entrance, fasten there, 
and attach the coverlid, forming a sort of hinge, so that being 
inclined in the direction of the soil, it falls back by its own 
proper weight, and the entrance of the habitation is always 
naturally closed. The contour of the door corresponds so well 
with that of the aperture, that it does not out-edge it in any 
place, that there is not the least vacancy in the joinings, and 
that the proportions could not have been better observed had 
they been taken by the compass. When this door, therefore, 
falls, it seals the entrance hermetically. The posterior con- 
vexity of the door also contributes to the precision of the 
closure. 
The Abbe Sauvages, from whom these observations are 
taken, was unable to discover the manner in which this 
animal proceeds in the formation of this nest, or its mode of 
subsistence and propagation. The individuals which he took 
alive, all perished, in spite of the cares which he employed 
for their preservation. 
This spider employs a singular degree of strength and 
address, when an attempt is made to open the door of its 
domicile. The observer just quoted, being desirous to raise 
it by means of a pin, experienced a resistance which he by no 
means expected. He saw the animal in a reversed attitude, 
hooked by the legs, on one side against the walls of the en- 
trance of the hole, on the other at the web, which covers the 
hinder part of its door, dragging the door to itself, so that in 
this struggle it opened and closed alternately. The mygale 
did not give way until the trap was entirely raised. It then 
precipitated itself to the bottom of the hole. Every time, 
when similar attempts were made, even at the slightest move- 
ment, the animal runs forward immediately, to hinder its 
door from being opened, and never ceases to keep guard there. 
If it be closed, one may work at the clay all about, and 
excavate it to carry off the habitation, without the peril with 
VOL. XIII. H ll 
