ORDER PASSERES. 495 



of the male assuming many dissimilar plumages, both before 

 he is clothed in the covering of maturity, and after he has 

 quitted it. This occurs even among the aquatic birds, both 

 waders and web-footed, and still more in the order now under 

 our survey. Among the sylvan birds it has, indeed, been 

 doubted, whether a double moulting ever takes place; but 

 the males of a great number of European species, have, in spring 

 and summer, different colours from those which they bear in 

 autumn and winter. With some they pass from an obscure 

 shade, to tints of deeper briUiancy ; while in others a perfect 

 contrast takes place. This last is the case with our black fly- 

 catchers of Europe: the gray tint of their wintry plumage 

 changes in spring, first to a pale black, and finally to a lus- 

 trous black on the upper parts. The white of the under parts 

 grows more pure, and finally assumes a snowy brilliance ; all 

 this takes place without any fresh moulting. This meta- 

 morphosis, and the very different livery of the females and the 

 young, have given rise to the creation of spurious species. 



AVe take the present opportunity of extracting the opinions 

 of Dr. Fleming concerning these changes in the colour of the 

 clothing of animals. The observations in question, originally 

 appeared in the Edinburgh Encyclopaedia, but we borrow 

 them from the Doctor's excellent work ' The Philosophy of 

 Zoology,' a work which, for cautious induction, close think- 

 ing, and sound and comprehensive views, is assuredly unparal- 

 leled in our language by any production on the same subject. 

 We are aware that no praise of ours can enhance its merits ; 

 but it would be ungrateful to withhold our acknowledgments 

 of the pleasure and profit which we have derived from its 

 perusal. 



" It has been supposed by some, that those quadrupeds 

 which, like the alpine hare and ermine, become white in 

 winter, cast their hair twice in the course of the year : at har- 

 vest when they part with their summer dress, and in spring 

 when they throw off" their winter fur. This opinion does not 



