Marvels of the Universe 



461 





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THE NEST OF THE 



same nest as that sKown o 

 door is open, balanced on the delica 

 has emerged, closes the lid down again over 



The 



[(,'./■,./,; s. 117,1'-. 

 TRAP. DOOR SPIDER. 



the opposite page, but here the trap- 

 ; silk hinse which, when the Spider 

 aperture. 



less than a tick of time, too swiftly, 

 indeed, for the human eye to follow 

 the consecutive details of the act. 

 The closing of the lid is effected auto- 

 matically, because the Spider cunningly 

 lays on the threads composing its 

 hinge in such a way that they are on 

 the stretch when the lid is open and 

 thus tend always to keep it shut. 

 But why. it may reasonably be asked, 

 is the Spider at such pains to conceal 

 the burrow and to capture prey with 

 such lightning speed ? Because, like 

 all spiders nearlj^ he hves in mortal 

 dread of those dire enemies of spiders, 

 the mason-\^'asps, which all through 

 the spring and summer are relentlessly ransacking every nook and cranny in the search for spiders 

 wherewith to provision the nests of their young. Against these powerful, venomous and armoured 

 insects the Trap-door Spider has no chance, even when fighting within the narrow precincts of the 

 burrow. 



The persecution of these insects, carried on generation after generation for untold thousands of 

 years, has had a wonderful influence in fashioning the structure of the burrows made by some species 

 of these Spiders ; for quite commonly the burrow is not a simple tube, but is complicated internally 

 by side-branches or secondary chambers, usually shut off by internal doors from the main part which 

 opens to the surface of the soil ; and it is interesting to note that in nearly all cases these additional 

 passages for escape are found in burrows which are closed by what have been aptly called, from their 

 deUcacy and thinness, " wafer " lids, to contrast them with the thick, heavy " cork " lids, with a 

 bevelled edge, which fit tightly into the slightly expanded aperture of the burrow. Nearly all 

 the cork-lidded burrows are simple tunnels, but many of those furnished with wafer-lids are more 

 complex ; and perhaps the most perfect burrow, from a defensive standpoint, that has yet been 

 discovered is that made by a species of Nemesia which occurs in South Europe. From a point 

 a short distance within the main burrow a second passage, mounting obliquely towards the 

 surface, is excavated ; and to the 

 upper edge of the orifice an inner door 

 is hinged in such a way that it can 

 be swomg upwards so as to block the 

 main passage, or pulled over the 

 aperture of the side tunnel. The 

 Spiders thoroughly understand the use 

 of the doors. If conscious of inter- 

 ference with the main door from with- 

 out, they quickly mount to it, and 

 grasping its inner surface with their 

 fangs and driving their claws into the 

 walls of the silk -lined burrow, hold on 

 with might and main to prevent it 

 being forced open. If unable to 

 resist the strength of the marauder, 

 the fate of the occupant is sealed 



I'hnlu kij] 



[ir. .V. lierrido,; I'.Z.S. 

 THE NEST OF THE TRAP-DOOR SPIDER. 



A view of the opposite nest in Situ. When the Spider h 

 the door of the nest is shut, the inmate holds on to the ins 

 by the mandibles and the first two pairs of feet 

 pairs are pressed against the walls of the tube. 



vhile 



entered and 

 iside of the door 

 third and fourth 



