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 vreight, 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 covei's 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 aniinal runs forward immediately, to hinder its 

 door fi'om 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 h 



