TRAP-DOOR SPIDERS. 81 



lias given an admirable description of one of these 

 single door wafer nests, the work of Cteniza nidulans, 

 which I cannot do better than quote : — ■ 



The nest is " cylindrical, or nearly so, from four to 

 ten inches deep, and about one inch in diameter ; the 

 bottom is rounded ; and the top, which is at the surface 

 of the soil, is closed very accurately with a circular 

 lid. They are not all equally finished, some being 

 much more compact, and having the lid more closely 

 fitted than others. Some have irregular bulgings, and 

 ragged laminated offsets on the outer surface ; but all 



are smooth and silky on the inside The mouth 



of the tube, and the parts near it, are very strong ; 

 the walls here often having a thickness of from one- 

 eighth to one-fourth of an inch ; but the lower parts 

 are much thinner. The lid is continuous with the 

 tube for about a third of its circumference, and this 

 part may be called the hinge, though it presents no 

 structure peculiar to itself ; it is simply bent at a right 

 angle, as is manifest, if a nest be cut longitudinally 

 through with scissors, the incision passing through 

 the midst of the lid. The mode of construction, I 

 judge, from examination of many nests, to be this. 

 The spider digs a cylindrical hole in the moist earth, 

 with her jointed fangs or mandibles, carrying out the 

 fragments as they are dislodged. When the excavation 

 has proceeded a little way, she begins to spin the 

 lining which forms the dwelling. I conclude thus, 

 because nests are occasionally found a few inches in 

 length, with the lid and upper |)art perfect, but without 

 any bottom, these being evidently in the course of 

 formation. I suppose that she weaves her silk at first 

 in unconnected patches, against the earthy sides. 



