122 Tlie Study of Animal Life parti 



details. Those of the land-crabs (Gecarcitius), the wood- 

 cutting bees {Xylocopd), the sand-martens, the marmots, the 

 rabbit, the prairie dogs, illustrate this kind of dwelling in 

 various degrees of perfection. 



The male stickleback (Gasterosfeics) weaves and glues 



Fig. 27. — Swallows {ChcUdonciria nrl'ica) and their nest. (After Brehm.) 



the leaves and stems of water-plants ; the minutest mouse 

 {AIiis miniiiiis) twines the leaves of rushes together ; the 

 squirrel makes a rougher nest ; the orang-utan and the 

 chimpanzee construct shelters among the branches ; but the 

 nests of many birds are by far the most perfect works of 

 animal art. 



Of buildings, the swallows' nests by the window and the 



