44 The Structure and Habits of Spiders. 



with web, to which they hold when at rest. 

 Several of the large running spiders dig holes 

 in sand, and line them with web, so that the 

 sand cannot fall in ; and build around the mouth 

 a ring of sticks and straws held together by 

 threads. 



TRAP-DOOR NESTS. 



The building of tubular nests is carried to 

 the greatest perfection by certain genera of the 

 Mygalida. (See page 13.) 



Atypus, the most northern genus of this 

 family, makes a strong silken tube, part of 

 which forms the lining of a hole in the ground, 

 and part lies above the surface, among stones 

 and plants, Fig. 22, A. The mouth of the 

 tube is almost always closed, at least when 

 the spider is full grown. 



Another genus, which lives in warm countries, 

 makes tubes lined with silk, and closed at the 

 top by a trap-door. A common species, Cteniza 

 Californica, lives in the southern part of Cali- 

 fornia, and is often brought east by travellers. 

 It digs its hole in a fine soil, that becomes, 

 when dry, nearly as hard as a brick ; but the 

 spider probably works when the ground is wet. 



