Year: 1867

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Scott Publishing Company


THE MnuCRY or ANNALS.


The leading article IN tins number OF the
"WestmmIstoIr is devoted TO curious discussion oi
the Mimicry of Animals considered as an illuSra-
ton of MI Darwin's theory OF the effect of Natural
Selection In the struggle for existence by the brute
creation The writer remarks that a necessary de
dnction from this theory s the utility which chaiao
terzes all the definite facts OF organic nature Ihefe
is no special organ, peculiar habit OF instinct ho
relations whatever between species or groups Oh
species that are not less useful To the iil-
yiduals or the races to which they belong Inc adap
tato, of the coIoripa Of animals to their condi-
tious Of If, il a striking instance OF the ap-
rIicotior nr this principle. CCnceaInent more or
less oonplete is essential TO the existence ol nu-
,uerous species Without this. they could neither
escape from their enemies, nor obtain their prey
The animals OF the desert accordingly, rule are OF
the color Of the desert The lion becomes almost in
visible when crouched upon the sand or among rocks
and stones. The antelope. the camel, the Egyptian
cat and the Australian kangaroo all Of the color
of sand OF earth. The birds of the desert have the
same hue The stOnechats, the arks the quails, the
goatsuckers, and the grouse, which abound in the
North African and Asiatlc deserts all tinted and
noted SO as TO resemble with wonderful accuracy the
average color and aspect of the soil in the district
they mhalit.


I'm like manner, as is well known, Arctic animals
have the white color that best conceals them upon
snowfeds and icebergs. The polar bear is the only
bear that Is white, and il lives constantly among
snow and ice. The Arctic fox, the ermine, ana the
Alpine hare are white only in Winter as III summer
that color would be conspicuous than any other
and rather expose them to danger than serve as q
protection: while the American polar mare, whlch
hives in regions of almost perpetual snow, is white
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fine example of protective coloring. Its Summer
plnmare so exactly haImonizes with the hchen-
oolored stones among which it delights to sit that
pereon NAV walk through flock of them without
seeing single bird; while in Winter ITS white
rlumage is an almost equal protection The snow
bunting. the erfalcon, and the snowy owl are also
white-colored birds inhabitng the arctic regions,
and there can be little doubt but that their cOlo1ng
s. TO some extent protective.


1t is only in the tropics, among forests which never
lose their foliage that find whole groups of birds
whose chief color green The parrots are the most
striking example but we have also group of green
pigeons in the East and the barbets eaf-thrushes,
beeeaters white-eyes, turacOs, and several smaller
groups have so much green i'll their plumage as to
tend greatly To conceal them among the foliage. In
a these cases. as in great variety of others enumer
pted by the writer cOncealment by peculiarties of
color IS one of the many ways by which animals are
enabled TO maintain successful struggle Tor eXls-
tence.


Rnt class of facts of similar import, though less
frequently noticed is found in the phenomena of
I'mimicry," by which is meant, not voluntary imta
ton of one animal by another, but resemblance IN
external experience adapted to catch the eve and TO
operate as disguise. 1t has been long known 10 en-
tomoogists that certain insects bear strange eXter-
nal resemblance TO others belonging to distinct gen
eral families, or even orders ard with which they
have no real affinity whatever. The fact, however,
appears TO have been generally considered as depend
ent upon some unknown law of analogy some
"system of nature OF general plan" which had
guided the Creator in designing the myTiads of insect
forms and which we could never hope TO understand


Recently, however these instances have been great
ly multiplied the nature OF the resemblances has been
more carefully studied, and 1t has been found that
they are often carried out into such details as almost
30 imply parpose of deceiying the observer. The
phenomena, moreover, have been shown 10 follow
Certain definite laws, which again all indicate their
dependence the more general law Of the survival
of the test" OF the preservation of favored races
IN the struggle for life" ThemOst striking instances
of this mimcry are found among the different classes
OF butterflies. There is IN South America an ex-
tensive family of these insects, the Heconide,
which are in many respects very remarkable. They
are SO abundant and characteristic in all the woody
portions of the American tropics, that IN almost
every locality they will be seen more frequently
than any other butterflies. They are dstin-
guished by very elODgate wings body. and an
tenne and are exceedingly beautiful and varied
IN their colOrs spots and patches of yellow red or
pure white upon black, blue, or brown ground,
being most general They frequent the forests
chiefly and all fly slowly and weakly; yet although
they are so conspicuous, and could certainly he


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most any other insect their great abundance all
the wide region they nhabit shows that they not
so prosecuted. 1t is to be especially remarked also
that they possess no adaptive coloring to protect
them during TepOse for the under side of their wings
presents the same at least equally conspicuous
colorng as the upper side; and they may be OBJ
served after sunset suspended at the end of twigs
and leaves where they have taken mp their station
for the night fully exposed to the attacks of the enc
mics they have any These beautiful insects possess
howevera strong pungent semi-aromatc or medicinal
OdOr which seems to pervade all the juices of their
system. When the entOmOlOgist squeezes the breast
of one of them between his fingers to Kill it, yell
low liquid exudes which stains the skin, and the
smell of which can only be got rid of by time and
repeated washngs Here We have probably the cause
of their immunity from attack, since there is great
deal Of evidence to show that certain insects are
disgusting to birds that they will under no cTcum-
stances touch them Now it is plain that any other
butterfly of a group which birds were accustomed to
devour would be almost equally we'll projected by
closely resembling a Heliconia externally if it also
had the disageeable OdOr, supposing that there
were only few of them among a
great number of the HecoDias. If the birds
could not distinguish the two kinds by their external
appearance, and there were on the average only
about one eatabe among fifty uneatable, they would
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