TRAP-DOOR SPIDERS. 129 



Do the young spiders build their first nest by in- 

 stinct — that is to say, independently of all teaching or 

 personal experience — or do they coj^y the nests in 

 which they were hatched ? 



What is wanting, however, is not discussion, of 

 which we have had enough, but demonstration, and 

 demonstration is hard to come by, depending as it 

 must upon careful and repeated experiment. 



If it were practicable, and I have no reason to know 

 that it is not, to rear spiders from the egg away from 

 the nest, and then to cause them to build in places 

 where they should be perfectly at home and yet cut 

 off from all communication with their kind, we might 

 liope to learn whether they can construct the charac- 

 teristic nests of their species without ever having 

 seen one. 



Mr. Wallace* shows that there is some reason to 

 doubt whether birds, which are so frequently said to 

 build by instinct, would, under parallel circumstances, 

 construct the nest proper to their kind ; and he states 

 that birds brought up from the egg in cages do not 

 do so, nor do they even sing their parents' song with- 

 out being taught. 



Of course we can scarcely compare birds and spiders 

 together, but we should hesitate, in view of Mr. 

 Wallace's expressed opinion as to the nest-building 

 habits of the former, to assume that the latter are 

 independent of teaching and personal experience. It 

 may very possibly be so, but it has never been proved. 



I have endeavoured to gather together all the pub- 



* Chapters on Instinct and on tlie Philosophy of Birds' Nests, in his Con. 

 tributions to the Theory of Natural Selection. 



K 



