TANAGBRS. THEIR GREAT VARIATION. 117 
(ISl.) We thus account for the little reliance that 
can be placed on the mere sise of the bills of the 
tanagers, for determining their genera ; but this will 
not explain the great difference which often takes place 
in the size and plumage of species, which all writers 
agree in placing within the limits of the same sub- 
genus : we might take the restricted genus Pitylus of 
Cuvier as an example of this, where some of the species 
are green, some black, and others grey ; and they vary 
from the size of a sparrow to that of a small thrush. 
W e cannot be accused of not favouring the adoption of 
new genera, and yet we are compelled to cancel that of 
Cissopus, from our present conviction that it is a mere sec- 
tional representation of Lanins in the subgenus Pitylus, 
which stands at the head of the tampers. The recent 
discovery, in fact, of its 
prototype, in the suhgenus 
Lanins itself, may be said 
to demonstrate this view of 
the subject; for a shrike, dis- 
covered by Dr. Smith in South 
Africa, is so completely like 
Cissopus (^Pitylus picatus,fig. 
iCS.), that, hut for their bills, 
the two birds might be easily 
mistaken for the same species ; 
both, in fact, are miniature 
magpies, and both represent 
that well-known bird in their own circles. 
(132.) We shall now give a rapid sketch of the views 
We at present entertain of the natural affinities of 
these birds, first briefly stating the doubts that still 
hang over their correctness. These doubts, indeed, may 
be said to hinge almost entirely upon our not having 
been able to examine specimens of the Fringilla Zena 
of authors, — a bird which, strange to say, seems not to 
exist in any of our public museums, and which we have 
in vain endeavoured to procure for our own. There 
are several peculiarities in this remarkable finch, which 
I 3 
