THE TRAP-DOOR SPIDER. 67 



as by the spider itself: this, however, is not 

 the case ; for repeated observation has shown 

 that the spider keeps guard at the entrance, and 

 actually holds the door with her fore feet and 

 palpi, while the hinder 

 feet are extended down 

 the side of the nest, 

 and the mandibles are 

 thrust into the oppo- 

 site side near the door. 

 By this means the in- 

 sect gets such power as 

 to resist with consider- 

 able force the opening 

 of the door. If it 



-, -. , , . TRAP-DOOR OPENING BY A LEVER. 



be asked how this is 



known, we are able to refer to the experiments 

 of careful observers, who extracted a number 

 of nests from the ground, and opening them at 

 the lower end, looked up, and saw the spider 

 so occupied. A sectional view of the nest will 

 show that the curved form of the cover, and 

 the shape of the side walls, must favour this 



