Lastly, the formation of the nostrils must not pass unobserved. | One of thé
typical characters of the Tyrant .Shrikes is to have the aperture perfectly round,
or at least very nearly so; and it is only among, some small species of Tyrannulè
that the membrane is so far developed as to reduce this opening to a more oval
form: but in the Old World Muscicapw the aperture is linear-oval, and in the typical species linear.
No satisfactory results have attended our attempts to draw characters from the
different modifications observed in the bills of these two races; and, indeed, when
we see how completely this member differs in size, form, and thickness, in such
birds as Tyrannus crassirostris and intrepidus, or again in Savanna and uudax,
we are convinced how futile will be all such attempts at present. The truth
appears to be, that almost every species, from our personal observations on these
birds, seems attached to certain species or genera of insects, which may be considered
its peculiar food ; and these, varying in size and habits, are captured by
bills of different modifications. The whole of Tropical America may be said to
swarm with the Tyrannince; so much so, that several individuals of three or four
species may be seen on the surrounding trees at the same moment, watching for
passing insects : each, however, looks out for its own peculiar prey, and does not
interfere with such as appear destined by nature for its stronger or more feeble
associates. It is only towards the termination of the rainy season, when myriads
of the Termites and Formica emerge from the earth in their winged state, that
the whole family of Tyrants, of all sizes and. species, commence a regular and
simultaneous attack upon the thousands which then spring from the ground.
On duly weighing the peculiar distinctions of the small American Tyrants, we
feel justified in the suspicion that they do not belong to the same group as the
genuine Muscicapce; while, on the other hand, these little birds are so blended
with the more typical Tyrants, that they can scarcely be detached from them even
as a genus. This will be manifest to any one who examines Tyrannus calcaratus,
ferox, and crinitus *, or Tyrannula Saya, querula, barbirostris, musica, or nigru
canst- The natural subdivisions of this group also require much investigation :
we can, indeed, feel little doubt that the typical genus is Tyrannus, and that the
T. crudelis* exhibits a greater perfection of structure than even the well-known
American Kingbird (T . intrepidus). Neither is it difficult to perceive that nature,
upon entering the group by means of Ptiliogonys, advances towards the Swallowtailed
Tyrants by two different routes; but one of these presents an hiatus, on its
* Journal of the Royal Institution. t Philosoph. Magazine and Annals, June, 1827, p. 366.
touching the confines of the true Laniadoe, which cannot be satisfactorily filled up
by any bird we know of. The only one which betrays a sufficient departure from
its type to justify an opinion of its close relation to Lanius is the common Tyrannus
sulphuratus, or B e n t i v i of Brazil. But the lengthened bill of this bird, viewed
in its supposed connexion with Tyrannus and Lanius, appears perfectly anomalous ;
for as this.member in the Tyrannince- is usually short, or at least moderate, and
in Lanius is still shorter, so we should expect to find in a bird which really connected
these .'groups, that the bill would have an intermediate length, or at least
not be prolonged more than that of any one bird in the two sub-families. That
the Bentivi, however, makes the nearest: approach to Lanius of any bird yet discovered,
is, we think, sufficiently evident ; not only from its greatly-compressed bill,
but by. feeding upon reptiles, and thus becoming partly, carnivorous. We have
more than once taken from the stomach of this species lizards in an entire state,
Sufficiently, large to excite surprise how they could possibly have been swallowed
by the bird. Azara likewise says, “ Les Biéntiveos (by which name this bird
is also known in Brazil) “ s’ approchent des animaux morts pour s’emparer'des débris
et des petits morceaux de chair que laissent les Caracaras,” &c. This, indeed, we
never witnessed, but we can well believe the fact ; not merely on the high authority
of such an observer as Azara, but as being supported by a peculiar structure in
the bird: .its claws, unlike those of all other Tyrants, are but slightly curvèd; thus
enabling the bird, when so engaged, to walk without difficulty upon the ground.
The length of the bill is, then, the only peculiarity in the Bentivi, which appears
anomalous ; nor can it, we apprehend, be explained in any other way than by comparing
it with the bills of certain Madagascar Shrikes, closely related to Tephro-
dornh, which group, be it remembered, stands on the confines of the Edolianoe.
In all these birds the prolongation of the bill, and its general form, are so much
the same, that it is impossible to deny an apparent relationship between them ;
nor do we hesitate in expressing our opinion, that the affinity which Saurophagus bears to Tephrodornis is to the full as great, if not greater, than that between
Saurophagus and any form yet discovered among the Lanianæ.
. That the Bentivi of itself is sufficient to prove the union of the three aberrant
groups of the Laniadoe must not, however, be inferred, any more than that it
actually connects the Tyrannince with the Lanianæ ; but that it exhibits, both in
* The striking dissimilarity between this bird and the true Tyrants induced us, some years ago, to detach it from
that group as a sub-genus, under the name of Pitangus, associating with it the broad-billed Lanius pitangua of Linnæan
authors. Much doubt, however, seems to hang over the true affinities of this latter bird ; and the above name, thus
rendered doubly objectionable, we propose to amend by substituting that of Saurophagus.r Another typical species has
recently come into our possession.—Sw.