in HERMIT HOMES 113 



indispensable, owing to the density of the lining 

 material and the tightly-fitting lid. The row round 

 the edge of the tube may be, as it were, a stock in 

 reserve in case of accident, should the lid holes 

 happen to become effaced with particles of the sur- 

 rounding earth. 



Some trap-door nests. of the south of Europe (see 

 Figs. 12 and 13) have thinner doors, less tough and 

 coarse in texture, and frequently they are not wedged 

 into the top of the tube like a stopper, they simply rest 

 over it. Often the excavation is amidst moss and other 

 low undergrowth, securing safety in obscurity of site. 

 The lower extremity may end in a short spur-shaped 

 enlargement. Sometimes a subsidiary branch is dug 

 obliquely upwards from the middle to the surface, 

 where it is lightly closed by a few silk threads ; usually 

 this shoot is a mere cul-de-sac (see Fig. 13). A 

 hanging-door exists at the junction of the two tubes ; 

 and at the depth of two or three inches down the 

 main one a door of the same kind may be found. 

 If an enemy, a parasitic fly, for example, force its 

 way into the nest by the principal, or the sole en- 

 trance, as the case may be, the spider is believed to 

 press up the last-mentioned door, leaving the intruder 

 to all appearances to an empty domicile. Should this 

 manoeuvre fail, and the hunter be not deceived by the 

 trick, the spider can dodge into the branch, and 

 draw the second door to behind him. Where the 

 branch extends to the surface, if needs be, he can 

 evacuate his premises and escape. 



Certain spiders" (Lycosides) raise a cylindrical 

 hollow tower over their burrow, much like an ordin- 



I 



