TRAP -DOOR SPIDERS. 237' 



the struggle for existence ; the times and seasons 

 of its activity, and in many cases even the struc- 

 ture and position of its dwelling-place will be 

 governed by this same all-important question of food- 

 supply. 



I have now detected the remains of insects, and of 

 ants especially, in the nest of every species of trap- 

 door spider which I have examined in situ ; very fre- 

 quently, however, one may open several nests in 

 succession without finding any of these dedris, and at 

 other times they will only be detected beneath the 

 existing bottom of the tube, layers of silk having 

 been spun over successive layers of refuse. 



The horny coats of ants form by very far the largest 

 proportion of these remains, and I have lately been 

 much struck by the number of instances in which, 

 while digging out ants' nests at Mentone, I have found 

 trap-door nests (especially those of JV. Manderstjerna 

 and N. Moggridgii) in their midst, the tubes often 

 traversing the very heart of the ants' colony and 

 coming into close contact with the galleries and 

 chambers of the ants. The doors in these instances 

 had almost always escaped my notice, and, indeed, 

 they so closely resembled the surface of the ground 

 that even when I knew, from having accidentally cut 

 across the tube below ground, that one of these doors 

 must lie near a given spot, 3^et I could only discover 

 it by following the passage from below upwards. 

 This perfect concealment is doubtless of essential 

 importance to the spiders' success in life, for, if they 

 once alarmed the whole colony of ants and let them 

 know the exact whereabouts of their lurking-place, 

 they would soon learn to avoid it. 



s 



