The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1867-08-21

genitors of modified races. Rapid multiplied
ton, incessant slight variation, and survival oil
the httest-these are the laws which ever keep |
the organic world in harmony with the inor-
ganic and with itself These are the laws
which we believe have produced all the cases
of protective resemblance already adduosd, as
well as those still more curious examples we
have yet to bring before our readers
1t must always be borne in mind that the
more wonderful examples, in which there Is
not only general but special resemblance
as in the walking leaf, the messy phasma, ana
the leaf-winged butter6y-represent those lew
instances in which the process of modihcauon
has been going on during an immense
series of generations. They all occur IN
the tropics where the conditions OF exist
ence are the most favorable, and Where
climatic changes have for long pc.
RODS been hardly perceptible. IN nosS
OF them, favorable variations Doth Oh
color form, structure, and instinct or habit
must have occurred to produce the perfect
adaptation we now behold. All these are
known to vary and favorable variations,
when not accompanied by others thaI Were
unfavorable, would certainly survive: AT one
time little step might be made in this direc-
ton, at another time in that-a change oil con-
ditions might sometimes render useless that
which it had taken ages to produee-great
and sudden physical notifications might often
produce the extinction of race just as 1t was
approaching perfection, and huddred checks
OF which we can know nothing may have re-
tarded the progress towards perfect adaptation;
SO that we can hardly wonder at the few cases
IN which result has been attained which is
shown to be successful by the abundance
and wide diffusion of the creatures so pro-
tected.
1t is as well here to reply to an objection
that Will no doubt occur to many readers,
that If protection is so useful to all animals,
and so easily brought about by variation and
survival OF the httest, there ought to be no
conspicuOusly colored creatures; and they
will perhaps ask how we account for the bril-
liant birds, and painted snakes, and gorgeous
insects that occur abundantly all over the
world. 1t will be advisable to answer this
question rather fully, in order that we may be
prepared to understand the phenomena of
''mimicry," which it is the special object of
this paper to illustrate and explain.
The slightest observation of the life of ami
mails will show us that they escape from their
enemies and obtain food in an infinite variety
of ways and that their varied habits and in
stincts are in every case adapted to the condi-
tions of their existence. The pOrcupine and
hedgehog have a defensive armOr that saves
them from the attacks of most animals. The
tortoise isnot injured by the conspicuous coors
of his shell, because that shell is in most
cases an effectual protection to him. The
skunks of North America find safety in their
power of emitting an unbearably offensive
odOr; the beaver in its aquatic habits and
solidly constructed abode. In some cases the
chief danger to an animal occurs at one par
ticular period of its existence, and if that is
guarded against, its numbers can easily be
maintained. This Is the case with many BIRDS
the eggs and young of which are espe-
pecially obnoxious to danger, and we find
accordingly variety of curious con-
trivances to protect them. We have nests
carefully concealed, hung from the slender ex-
tremitieS of grass or boughs over water, or
placed in the hollow of a tree with very
small opening. When these precautions are
successful so many more individuals will be
reared than can possibly find food during the
least favorable seasons, that there will always
be number of weakly and inexperienced
young birds who will fall a prey to the
enemies of the race, and thus render necessary
for the stronger and healthier individuals no
other safeguard than their strength and actv-
ity. The instincts most favorable to the pro-
duction and rearing of offspring will in these
cases be most important, and the survival of
the tittest will act so as to keep up and adj
vance those instincts, while other causes which
tend to modify color and marking may continue
their action almost unchecked.
1t is perhaps in insects that we may best
study the varied means by which animals are
defended or concealed. One of the uses of the
phOsphorescence with which many insects are
lulmsned IS probably to trghten away their
enemies; for Kirby and Spence state that
ground beetle (Carabus) has been observed
running round and round luminous oentipede
as if afraid to attack it. An immense number of
insects have stings, and some stingless ants of
the genus Polyrachis are armed with strong and
sharp spines on the back, which must render
them unpalatable to many of the smaller in
sectivorous birds. Many beetles of the family
Curculionide have the wing cases and other
external parts so excessively hard, that they
cannot be pinned without first drilling a hole
to receive the pin, and it is probable that all
such find protection in this excessive hard
ness Great numbers of insects hide them
selves among the petals of flowers, or in the
cracks of barks and timber; and finally, ex-
tensive groups and even whole orders have a
more or less powerful and disgusting smell
and taste, which they either possess perma-
nently, or can emit at pleasure. The atti-
tudes of some insects may protect them, as
the habit of turning up the tail by the harm
less rove-beetles (Staphylinid@) no doubt
leads other animals, besides children, to the
belief that they can sting. The curious
attitude assumed by the sphinx cater
pillars is probably safeguard, as well as
the blood-red tentacles which can sud- |
denly be thrown out from the neck, by the
caterpillars of all the true swallow-taled but |
terfies.
1t is among the groups that possess some
OF these varied kinds of protection in a
high degree, that we find the greatest
amount of conspicuous color, or at least the
most complete absence of protective imitation.
The stinging HymenopteTa, wasps, bees and |