DWELLINGS. 20$ 



little cup of earth is full to the edge. When the 

 dwelling is thus prepared and provisioned, the insect 

 lays an egg there and closes the upper part with a 

 vault, built by successive deposits over the opening, 

 which is more and more narrowed until it is finally 

 shut up. Having completed a chamber, it passes on 

 to the next, and so on until it has assured the- fate of 

 all its descendants. 



This hymenopterous insect certainly shows in its acts 

 as an artisan an inevitable instinct : hereditary intelli- 

 gence has become less personal and less spontaneous. 

 In certain cases, however, the instinct loses its rigidity 

 and automatism. Thus, when a Chalicodoma, at the 

 moment of preparing to accomplish its task, finds an 

 old nest, still capable of repair although dilapidated, 

 it does not hesitate to take possession of it and to 

 silence its assumed innate instinct of building. It 

 profits by the work already done, and is content to 

 fill up the cracks or to re-establish the masonry where 

 defective ; then it provisions the renewed cells with 

 honey, and lays its eggs in them. In certain circum- 

 stances it shows itself still more sparing of trouble, 

 and boldly rebels against the law which seems to be 

 imposed on it by nature. If it feels itself sufficiently 

 strong, the Chalicodoma throws itself on one of its 

 fellows, a peaceful constructor that has almost com- 

 pleted its work; it chases it away, and takes possession 

 of its property to shelter its own eggs. Instead of 

 manufacturing the cell from bottom to top, it has 

 only to complete it. Such acts evidently show the 

 reflection appearing through instinct 



Besides the Swallows, of which I have already 

 spoken, birds offer us several types of skilful con- 

 struction with tempered earth. 



