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ENTRODUCTION: XX1

All the members of the genus Ramphomicron are said to feed on insects which inhabit the alpine Flore;
and their bill is well suited to the capture of the minute insects found in those elevated regions. In some
instances the bill is perfectly wedge-shaped, as in Heliothrix ; while in others it suddenly turns upwards, as
in Avocettula. These forms are also adapted for some special purpose, of which, however, at present we
are ignorant. Besides these, there are others whose bills approach somewhat to the form of the Flycatchers,
as the dithurus. This bird, we know, frequently seizes insects on the wing ; and so doubtless do many of the
others. It will have been seen that all these forms of bill are well suited for the capture of insects ; and,
as might be supposed, insects constitute the principal food of the Humming-Bird ; but that liquid honey,
the pollen, and other saccharine parts of flowers are also partaken of, is evident from the double tubular
tongue with which all the species are provided. Besides this, they readily and greedily accept this kind of
food when offered to them in a state of captivity, or when the corollas of a bouquet of flowers placed in a
window are filled with sugar to entice them to approach; and from my own experience I know that they

have been kept in captivity for several months upon this kind of food.

Connected intimately with the mode of flight is the form and structure ot the tail; and in no group of
birds is this organ more varied ; in some species it is four times the length of the body, in others it is so
extremely short as to be entirely hidden by the coverts. As cases in point I may mention Leshia Amaryllis
and Calothorax micrurus. Every Humming-Bird, however, has ten tail-feathers, and no more. I am aware
that this number is not apparent in some of the smaller fork-tailed species, the two centre-feathers being so
exceedingly minute as to be almost obsulete ; but if a careful examination be made, that number will be

found. I may instance Thaumastura Core, Doricha enicura, and Myrtis Fannie.

The tail appears to be, and doubtless is, a very important organ in all the aérial movements of the
Trochilide ; and accordingly we find very great variations in its form among the many different genera of
which the family is composed. In Cometes and Lesbéa, the forked character is carried to its maximum, while
its minimum is seen in Calothorax, Acestrura, and the allied groups. The tails of all the members of the two
former and many other genera are of this form; while in others it is only seen in a single species of a
group, all the other members of which have rounded, square, or cuneate tails. As a case in point I may
cite Eupetomena macroura, among the Campylopteri, which may be regarded as the aérial type of its own
particular group. Next to this we may notice the species with feathers terminating in spatules, such as
Loddigesia, Spathura, etc. I was informed by the late Mr. Dyson that the flight of these birds presents a
marked difference from that of other Humming-Birds, and that their appearance in the air is most singular,—
the tail being not only constantly opened and shut, but the spatules always in motion, particularly when the
bird is poising over a flower; and if this be really true, what an extraordinary appearance must the Loddi-
gesia mirabilis present during its evolutions! But we cannot attempt to describe it ; the discovery of a second

example, and the peculiarity of its flight, must be left for future historians to make known to us.

In some few instances, such as Julamyia typica and Sphenoproctus Pampa, the tails are cuneate ; but this
form is quite exceptional, if we exclude the Phaéthornithes and Eutoweres, in which this is the prevailing form.
Besides the groups with forked or cuneate tails, there are others in which this organ is square or rounded,
as in the Florisuge and Metallure. The reverse of the spatulate form occurs in some species, such as the
members of the genus Gouldia, in which the tip of the outer tail-feathers terminates in thread-like filaments.
The citation of one more will be sufficient to show how widely different is the form of this organ among

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