TUNNEL ENTRANCES. 



169 



which would be only too glad to get into an igloo and make a 

 meal of its inhabitants. The Esquimaux architect, therefore, 

 avails himself of an ingenious device by which he can set both 

 foes at defiance. 



In summer-time he contents himself with a hut made of 

 skins, and merely hangs a skin over the entrance by way of a 

 door. But in the winter, when he is driven to his snow-house 



NESTS OF FATRY MARTIN. 

 TOWERS OF SAND -WASP. 



HUTS OF ESQUIMAUX. 



for shelter, he acts in a very different manner. Instead of 

 merely cutting an aperture for a door in the side of the igloo, 

 he constructs a long, low, arched tunnel, so small that no one 

 can enter the igloo except by traversing this tunnel on his 

 hands and knees. Sometimes a number of huts are con- 

 nected with each other, one or two tunnels leading into the air, 

 and the rest serving merely as passages from one hut to the 

 other. 



In Nature are several examples of tunnels constructed on 

 the same principle. 



There are, for instance, the curious nests of the Fairy Martin 

 of Southern Australia (Hirundo Ariel), which bear a singular 

 resemblance to oil-flasks, the body of the nest being rather 

 globular, and the only entrance being through a tolerably long, 

 tunnel-like neck. 



Then there are the various Weaver-birds of Africa, with 

 their long-necked nests. Some of these strange edifices look 



