Weavers and Spinners. 



be asked, is the use of the branch ? I do not think 

 that we can draw any safe conclusion from what takes 

 place when we dig out a spider as to what would occur 

 if she were besieged by one of her natural enemies, 

 such as ichneumons, sand-wasps, or centipedes. Let us 

 suppose, however, that one of these creatures has found 

 its way into the nest, and is crawling down the tube. 

 What will happen ? Why, in the first place, the spider 

 will slam the second door in the face of the intruder, 

 and then, if worsted in the pushing match which follows, 

 quickly draw this door back again and run up into 

 the safety branch, when the enemy, after descending 

 precipitately to the bottom of the main tube, will look 

 in vain for the spider, as it searches on its way up for 

 the secret passage now closed by its trap-door." 



In the unbranched double-door nest the thin and 

 wafer-like surface door appears to be constructed by 

 the Trap-door Spider to serve principally for conceal- 

 ment, while the lower one is for resistance. This lower 

 door is made out of earth encased in strong white silk, 

 and has at the end opposite the hinge a sort of silken 

 flap, by which the door when firmly jammed into the 

 tube on the approach of an enemy may be pulled 

 down again as soon as the danger is over. But of all 

 these nests, the cork, type, as Mr. Moggridge calls it, 

 is the cosmopolitan form, which ranges round the world, 

 and, strange to say, is built by many different spiders 

 belonging to distinct genera. In fact, " this very per- 

 fect bit of mechanism appears to be the common in- 

 heritance of these several spiders, separated though 

 they are by wide intervals of geographical space as well 

 as of structural divergence. " 



