HOW SPIDERS DIG 



ning an entirely new nest, the tunnel she has to dig will be 

 about an inch in diameter, and perhaps nine inches in depth. 

 The excavation of such a tunnel is no small undertaking, 

 for these spiders are not very swift in their movements, and 

 the digging is done principally with the mandibles and their 

 fangs, the legs taking no part in the proceeding. In other 

 families of spiders the mandibles strike sideways, but in the 

 Territelarice they strike downwards, a modification which is 

 probably connected with their digging habits. The earth 

 is removed in tiny pellets and taken some distance away 

 from the nest, every pellet being carried forward in the jaws 

 and deposited separately on the tip. It is a slow process, 

 but in an hour the spider succeeds in digging a hole about 

 the size of half a walnut. As it becomes deeper the removal 

 of the fragments becomes more laborious, but no other 

 method appears to be adopted. Before the tunnel has attained 

 any great length the spider, like a good engineer, very 

 wisely shores up the walls with patches of silk to prevent 

 them falling in upon her, and afterwards covers them entirely 

 with several layers of the same material. She also makes 

 the door before the excavation is finished, and a moment's 

 consideration will show the advantage of this order of pro- 

 cedure. The labour is long and occupies a considerable 

 time, and while so engaged the spider is especially open to 

 attack. Mr. Bates stated that he had frequently seen certain 

 species of the genus Pepsis, insects which are allied to wasps, 

 on the Amazon, hawking over the ground where the huge 

 trap-door spiders lived, and suddenly pouncing down upon 

 one of these creatures, often many times larger than them- 

 selves ; then, after paralysing their victim with their sting, 

 they would deliberately saw off the legs before dragging 

 away the body. With such terrible enemies to harass her, 

 it is not to be wondered at that the spider prefers to work 



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