118 ON THE CLASSIFICATION OP BIRDS. 
lead US to suspect that it forms the type of one of the 
principal divisions among the tanagers, or that it 
connects our genus Agla'ia with Pipillo. On the first 
supposition, F. Zma would constitute the passage from 
the true sparrows (Pyrgihi) to the suhgenus Tanagra 
proper ; while, by the second, Pipillo would stand inter- 
mediate between AglcCia and Tanagra, and thus consti- 
tute the rasorial genus of the whole subfamily. This 
latter arrangement certainly appears to us the most 
likely to be the natural one, in which case, F. Zena ; 
will be merely a subgenus, either of Pipillo, or of 
AglaU; or, in other words, will connect the two. 
Neither can we, by any disposition we have yet made, 
discover the circular series of the types of form in the 
genera Tanagra and Plmnisoma, chiefly from ignorance 
of the real affinities of jlrrcmon : but for this, — and 
supposing the tenuirostral types of these two genera to 
be undiscovered, — we feel some confidence in the series 
in which we have disposed the remaining groups. We 
take this opportunity of soliciting, from any of our 
ornithological readers, the use of a specimen of F. Zerta, 
or of those few species which seem to possess the same 
form. 
(13.8.) The following arrangement of the tanagers, 
under the foregoing difficulties, must therefore be looked 
upon for the present as provisional. We consider that 
the two typical groups or genera are Tanagra and 
Phosnimma ; while those which we think aberrant are 
Nemosia, Agla'ia, and Pipillo. It is only between the 
two last of these, that we cannot as yet discover any 
affinity, at least, sufficiently strong to justify tlie behef 
that these five genera form a circle “ more or less 
complete the difficulty, as before stated, being how 
to connect Agla'ia with Pipillo. In taking a slight re- 
view of these genera, we shall begin with Tardivola, 
whose absolute connection to Pitylm has been already 
proved. We then proceed to the restricted group of 
Tanagra, where we have aU those tieautiful birds of 
a cinereous blue colour, so many species of which we 
