SPIDERS. 139 



interest in natural history can pass this nest without pausing in 

 admiration. The workmanship is wonderful, and the hole, with 

 its cover, looks as if it had been made in clay, by means of the 

 potter's wheel, so regular and true are its outlines. The hole it- 

 self is circular, but the door is semicircular, the hinge extending 

 across the middle of the aperture. 



Two points in this door are specially worthy of notice, the one 

 being that its edge, as well as that of the aperture, is beveled off 

 inward, so that the accurate closure of the entrance is rendered a 

 matter of absolute certainty. The second point is, that the outer 

 surface of the door, together with the surrounding earth, is ingen- 

 iously covered with little projections, so that when the door is 

 closed, the line which, on smooth ground, would have marked its 

 presence is totally hidden. The shape of the door, too, is remark- 

 able. Toward its hinge it is comparatively thin, but upon the 

 edge it is very thick, solid, and heavy, so that its own weight is 

 sufficient to keep it firmly closed. The "hinge," to which allu- 

 sion has frequently been made, is not a separate piece of work- 

 manship, but is a continuation of the silken tube which lines the 

 tunnel. An exact imitation of its principle may be made by 

 taking the cover of a book, and cutting it across from the inside, 

 until all its substance except the cloth or leather is severed, and 

 then bending the two portions back. The cloth or leather will 

 then form a hinge precisely similar to that of the Trap-cloor Spi- 

 der, the pasteboard taking the place of the earthen door. 



