96 SPIDERS [CH. 



responsible for this action. Moggridge removed the lid 

 of a tunnel and also cleared the ground immediately 

 round it of all vegetation ; nevertheless, when the 

 spider made a new door, it covered it with moss taken 

 from the undisturbed vegetation beyond, so that the 

 trap-door was now conspicuous as a green oasis in a 

 sandy desert ! And on another occasion a spider 

 interwove fragments of scarlet fabric left purposely 

 at hand into the lid of its tunnel. It is clear, there- 

 fore, that the decoration of the door is due to an 

 instinct which impels the spider to utilise any 

 material of the neighbourhood without any regard 

 to the effect produced. 



The tube is densely lined Avith silk, which affords 

 its architect a secure foot-hold, and if any enemy 

 attempts to open the lid from without, the spider 

 resists with all its strength which is not incon- 

 siderable clinging on to its under surface with its 

 front legs and jaws, while the claws of its other feet 

 grasp the silken walls of the tube. 



The other type of trap-door is less interesting and 

 much more elementary, consisting simply of a wafer- 

 like sheet of silk mixed with earth and vegetable 

 matter, but it is a curious fact that while all known 

 trap-door nests of the cork type are simple tubes, 

 the burrows with wafer doors are often much more 

 complex. In some cases there is a branch tube, like 

 that constructed by Lycosa picta, leaving the main 



