472 HABITATIONS OF INSECTS. 



joining earth as not to be distinguishable from it. This 

 door the ingenious artist fixes to the entrance of her 

 gallery by a hinge of silk, which plays with the greatest 

 freedom, and allows it to be opened and shut with ease j 

 and as if acquainted with the laws of gravity, she inva- 

 riably fixes the hinge at the highest side of the opening-, 

 so that the door when pushed up shuts again by its own 

 weight. She has not less sagaciously left a little ledge 

 or groove just within the entrance, upon which the 

 door closes, and to which it fits with such precision, 

 that it seems to make but one surface with it. Such is 

 the astonishing structure of this little animal's abode ; 

 nor is its defence of its subterraneous cavern less sur- 

 prising. If an observer adroitly insinuates the point of 

 a pin under the edge of the door, and elevates it a little, 

 he immediately perceives a very strong resistance. — 

 What is its cause ? — The spider, warned by the vibra- 

 tions of the threads which extend from the door to the 

 bottom of her gallery, runs with all speed to the door, 

 fastens its legs to it on one side, and on the other to 

 the walls, and turning upon its back, pulls with all its 

 might. Thus the door is alternately shut or opened, as 

 the exertions of the observer or of the spider prevail. 

 It is easy to guess which will in the end conquer ; and 

 the spider, when it finds all resistance inefl'ectual, be- 

 takes itself to flight, and retreats. If, to make a further 

 experiment, the observer fastens do^\n the door so 

 that it cannot be forced open, the next morning he will 

 find anew entrance, with a new door formed at a small 

 distance ; or, if he take the door entirely away, an- 

 other will be constructed in less than twelve liours. 

 The habitation thus singularly formed and defended 



