126 



LEUCOCIRCA, 



from the circumstance of several of the species 

 having more white ahout their tails than any other 

 fly-catching birds yet discovered. It is, in truth, 

 now become a matter of no small difficulty in orni- 

 thology to frame generic names, expressing a 

 peculiarity of structure or of habit, sufficiently 

 different from those at present in use, to answer 

 the object proposed. Names taken from the various 

 constructions of the bill, wings, tail, and other 

 members, are completely exhausted; while the com- 

 parative ignorance in which we remain regarding 

 the habits of foreign birds, is an effectual bar to our 

 compounding names founded upon such circum- 

 stances. We have hardly any other resource, there- 

 fore, left to us, but to employ designations derived 

 from other peculiarities ; and as we find that many 

 natural groups are nearly as much distinguished by 

 colour as by structure, there appears no valid objec- 

 tion to deriving our names occasionally from this 

 source, as well as from structure or from habits. 

 But to return. The sub- genus Lettcocirca, as far as 

 we yet know, is restricted to the tropical latitudes 

 of the Old World, but more especially to India and 

 its islands, where it represents the last division. 

 That it immediately follows Rhipidura, not a doubt 



