OF THE INTELLIGENCE AND OF INSTINCT. 



167 



Fig. 120. Nest of the Mygale, or 

 Bird Spider. 



rough, like the neighbouring soil, so as to elude observation ; 

 the pit forming the den is dug in argillaceous earth, and 

 lined interiorly with a kind 

 of extremely consistent mor- 

 tar, and a lid or covering 

 is worked with alternating 

 layers of miry earth and 

 threads reunited into a tissue, 

 made to fit exactly and to 

 open only outwards. The 

 hinge supporting this cover- 

 ing is formed by a continua- 

 tion of the filamentous layers 

 proceeding from a point of 

 its contour upon the walls of 

 the tube situated beneath it, 

 forming there a pad or hood, 

 performing the office of a 

 mantle-tree. 



Among insects also may be observed many remarkable 

 instances of singular instincts in the construction of dwellings. 

 The larva of a small nocturnal butterfly, the tortrix viridis- 

 sima, is one of these ; it 

 lives on the oak, rolling- 

 up its leaves and connect- 

 ing them together with 

 threads. Others, as the 

 cloth moth, a small grey 

 and silvery papillon or 

 moth, which, when in the 

 larva state, rapidly breaks 

 up woollen stuffs, forming 

 galleries in the thickness 

 of the web or cloth. With 

 the hairs or wool thus 

 detached it forms long 

 tubes as a dwelling ; and 

 what is singular is, that when this becomes too small to 

 contain it, it breaks it open and adds to its length. 



Hybernating animals show singular instincts tending to 

 their preservation : they prepare a winter dwelling, and shut 

 it in, as if conscious or aware that they would not require to 

 leave it for a long period ; also to protect them from the access 



Fig. 121. Nest of the Tortrix; Oak-leaf 

 rolling Caterpillar. 



