The Black-Bellied Tarantula 17 



Economy of time, therefore, causes the 

 defensive wall to vary greatly as regards its 

 constituent elements. The height varies also. 

 One enclosure is a turret an inch high ; another 

 amounts to a mere rim. All have their parts 

 bound firmly together with silk ; and all have 

 the same width as the subterranean channel, 

 of which they are the extension. There is here 

 no difference in diameter between the under- 

 ground manor and its outwork, nor do we 

 behold, at the opening, the platform which the 

 turret leaves to give free play to the Italian 

 Tarantula's legs. The Black-bellied Tarantula's 

 work takes the form of a well surmounted by 

 its kerb. 



When the soil is earthy and homogeneous, 

 the architectural type is free from obstructions 

 and the Spider's dwelling is a cylindrical 

 tube ; but, when the site is pebbly, the shape 

 is modified according to the exigencies of the 

 digging. In the second case, the lair is often 

 a rough, winding cave, at intervals along whose 

 inner wall stick blocks of stone avoided in the 

 process of excavation. Whether regular or 

 irregular, the house is plastered to a certain 



