The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1867-08-23


! hopus formosus both being found IN many
| localities of tropical South America, -
What adds much TO the extraofolnary
character of these resemblances Is the ldoV,
that nowhere in the world but IN America
are tbere apv snakes at all which have this
st,lo of ooloriug Dr. Gunther of the
RTitisb Museum who has kindly furnished
tbe details here referred to, assures us that
this is the case and that red, black and
yellow rings occur together on no other
snakes in the world but on Flaps and the
species which so closely resemble it. In all
these cases the size and form, as well as the
coloratiOn, are SO much alike that none but a
naturalist would distinguish the harmless
from the poisonous species.
Many of the small tree-frogs are no doubt
also mimickers. When seen in their natural
attitudes, we have been often unable to dis
tinguish them from beetles or other insects
sitting upon leaves; but regret to say we
neglected to observe what species or groups
they most resembled, and the subject does not
yet seem to have attracted the attention of
naturalists abroad.
In the class of birds there are a number
of cases that make some approach to mimi
cry, such as the resemblance of the cuckoos,
a weak and detenseless group of BIRDS to
hawks and Galliuac5e There is, however,
one example which goes much further than
this, and seems to be of exactly the same
which have been already given, In Australia
and the Moluccas there is genus of honey
suckers called TropidOrhynchus, gOod-sized
birds, very strong and active, having power
full graspug claws, and long, curved, sharp
beaks. They assemble together in groups
and small focks, and they have a very loud
bawling note, which can be heard at a great
distance, aud serves to collect a number to-
gether in time of danger. They are very plen-
nj oY,I frnuupItlN
away crows and even hawks which perch
on a tree where a few of them are assem-
bled. They are all of rather dull and obscure
cOlors. Now, in the same countries there
is group of orioles, forming the genus
Mimeta, much weaker birds, which have
lost the gay colOring of their allies, and are
usually olive green or brown, and in several
cases they have come to resemble most curl
ously the Tropidohynchus of the same
island. For example, in the Island of Bouru
is found the Tropdorhynchus bOuruensis of
a dull earthly color and the Mimeta bouru-
ensis, which resembles it in the following par
ticulars:-The upper and under surfaces of the
two birds are exactly of the same tints of dark
and light brown; the Tropidorhynchus has a
large bare black patch round the eye; this is
copied in the Mimeta by a patch of black
feathers. The top of the head of the Tropidor-
hynchus has scaly appearance from the
narrow led-fOrmed feathers, which are imi-
tated by the broader feathers Of the Mimeta
having dusly line down each. The
Tropidorhynchus has a pale ruff formed
of curious recurved feathers on the
nape (Which has given the whole genus
the name of Friar birds); this is repre-
sented in the Mimeta by pale band in
the same position. Lastly, the bill of the
Tropidorhynchus is raised into a protube-
rant keel at the base, and the Mimeta has
the same character, although it is not COM
| mon one in the genus. The result is that, on
! a superficial examination, the birds are iden-
tical, although they have important structural
differences, and cannot be placed near each
| other in any natural arrangement.
Here, then, we have two cases of perfect
| mimicry and two others of good approXima-
tion, occurring between species of the same
two genera of birds; and in three of these
cases the pairs that resemble each other are
found together i'll the same island, and to
which they are peculiar. In all these cases
the Tropidorhynchus is rather larger than
the Mimeta but the difference is not be-
yOnd the limits of variation in species, and
the two genera are somewhat alike in form
and proportion. There are, no doubt, some
special enemies by which many small birds
are attacked, but which are afraid of the
Tropidorhynchus (probably some of the
hawks), and thus it becomes advantageous
for the weak Mimeta to resemble the strong,
pugnacious, noisy, and very abundant Tropi-
dOrhynchus.
Among the Mammala the only case which
may be true mimicry is that of the insectivo-
rous genus Cladobates, found in the Malay
countries, several species of which very closely
resemble squirrels. The size is about the
same, the long bushy tail is carried in the
same way, and the colors are very similar. In
this case the use of the resemblance
must be to enable the Cladobates to approach
the insects or small birds on which it feeds,
under the disguise OF the harmless fruit-eating
squirrel.
Having now completed our survey of the
most prominent and remarkable cases of
mimicry that have yet been noticed, we must
say something of the objections that have
been made to theory of their production given
by Mr.. Bates, and which we have endeavored
to illustrate and enforce in the preceding
pages. Three counter explanations have been
proposed. Professor Westwood admits the
fact of the mimicry and its probable use to the
insect, but maintains that each species was
created a mimic for the purpose of the protec-
ton thus afforded it. Mr.. Andrew Murray, in
his paper on the "Disguises of Nature" in
olnes to the opinion that similar conditions of
food and of surrounding circumstances
have acted in some unknown way to pro-
duce the resembances; and at a recent
meeting of the chronological Society of
London; when the subject was discussed,
DR.. Sharp maintained a similar view and
added a third Obiection-that hereditary or
the reversal to ancestral types of form and
coloration, might have produced many of the
cases of mimicTy.
ha mo-