~ 
ae 
114 ON THE CLASSIFICATION OF 1 BIRDS. Hs 
ae 
the most vivid husk or glossed with rich reflectio: 
gold, rendering them inferior only to the a bin ) 
Some possess considerable vocal powers; and the r 
of, the subgenus Euphonia, as its name implies, are s a 
to be particularly musical. The impossibility, however 
of providing the tanagers with their native insect food 
has prevented them from ever being brought alive to the 
European menageries, to which their beauty would rende: 
them the greatest ornaments. q 
(129.) It might be supposed, that the intern a 
arrangement of a group, distinguished by so many 
peculiarities, both of structure, colour, and geographic 
distribution, would be by no means difficult ; yet the 
very reverse of this is the case. We may safely affirm, 
indeed, that it is one of the most difficult to be under- 
stood in the whole circle of ornithology: nature seems 
to have departed, in this group, from that uniformity 
of progression which is so prevalent in all her works 
this remark is not applied merely to the smaller groups, 
but actually, in many instances, to the succession of 
species. The comparative strength of the bill, for 
instance, is so variable in birds of the same subgenus 
(the lowest denomination of groups that we can trace), 
that this variation, indicative of genera in other fami- 
lies, is in this no more than a discrimination of sections i 
or species. Nothing can illustrate this fact more-than: 
the affinity between Pitylus (fig. 163. b) and Tardivola. 
Looking to the types of each, we should say they 
did not belong even to the same subfamily; for the 
bill of the first is nearly as large as in the hawfinches 
(Coccothraustes), while that of Tardivola (a) is so com- 
paratively slender, that it seems more akin to the larks cs. 
than to the tanagers: and yet, between these tw 
extremes or types, we have now before us such a perf = 
series of graduated forms, wherein not only the bi 
but ali the other subordinate characters of the tw 
groups, progresses in such a beautiful and almost i 
perceptible manner, that we are actually at a lowall 
know where Turdivola ends, and Pitylus begins. 
t 
1 
’ a 
me oe tres 
