Evening star. [volume] (Washington, D.C.) 1854-1972, 1877-10-13

SINGULAR POWER OF ADAPTATION IN
CERTAIN INsECrs-FAcrs FOR sCIES-
Mr. A r. Wallace, writing on the subject
OF color in animals, says that q few We irs
seo Mr.. L. w. Wood called attention 10 the
curious changes of color of the chry sails OF
the small cabbage butterfly (Pontia Rspn)
when the caterpillars were confined in boxes
lined with different tints. Thus, in black
boxes, they were very dark in white boxes
nearly white; and he further showed that
similar changes occurred in q state of nature,
chry salises fixed against q whitewashei wall
being nearly white, against red brick wall
reddish, against a pitched pailing nesrly
black. IL has SlsO been observed tina the
cocoon OF the emperor moth is either white
or brown, accord ng TO the surrounding col
Ors. But the most extraordinary example of
this kind of change is that furnished by the
chTysalis OF an African butterfly (Papilio
Nireus) observed at the Cape by Mrs. Barber
transactions of the chronological Socie-
ty," 1874, page $40. The caterpillar feeds on
the orange tree, and also on a forest tree
tNepris lanceOlata) which has lighter green
leaf, and its color corresponds with tina, of
the leaves 1t feeds upon, being of d ker
green when IL feeds on the orange The
chrysalis is usually found suspended among
neighbOring tree; but il is often attached to
the larger branches, and Mrs. Barber has dis
covered that Ii has the property of AGO uiriny
the color, more or rs accurately, of any
natural object II may be in contact with. A
number of the caterpillars were placed In a
case with glass cover, one side of tn case
being formed by red brick wall, the other
sides being of yellowish 'wood. they were
led on orange leaves, and a branch OF the
bjttle-orush tree tBanksia, sp.l was placed
also in the case. When fully fed, some at
tachsd themselves to the orange twigs, others
10 the bottle brush branch; and these all
changed 10 green pupa; but each correspond
ed exactly In tint to the leaves around it, the
one being dark, the other a pale, faded green.
Another attached itself to the wood, and the
pupe became of the same yellowish color,
while one fixed itself just where the wood
and brick Joined, and became one side red,
the other side yellow. These remarkable
changes would, perhaps, not have been cred
tied, had II not been Tor the previous obser-
vattons of Mr.. Wood; but the two support
each other, and oblige US to accept them as
actual phenomena. 1t is kind of natural
Photography, the particular colOred rays to
which the fresh pupG is exposed in its soft,
semi transparent condition. effectiug such
chemical change in the organic ju ces
as to produce the same tint in the
hardened skin; 1t is interesting. how
that can be acquired seems TO be limited to
those OF natura! objects TO which the pupae
is likely TO be attached; for when Mrs. Barber
surrounded one of the caterpillars with a
piece of scarlet cloth no change OF color al all
was produced, the pupR being of the usual
green tint. but the small red spots with which
IL is marked were brighter than usual. In
these caterpillars and pupfe, as well as IN the
great majority OF cases in which change of
color occurs in animals, the action is quite
animals the color OF the integument can be
modified at the Will of the animal, or, at ali
events, by reflex action dependent on SEN
SatiOn. The most remarkable case of this
Kind occurs with the chameleon, which has
the power of changing It's color from a dun
white to a variety OF tints. This singular
power has been traced TO two layers of pig
ment deeply seated in the skin, from VIII oh
minute tubes or capillary vessels rise 10 the
surface. The pigment layers are blush and
yellOwish, and by the pressure or suitable
muscles these can be forced upward either to-
gether or separately. When no pressure is
exerted the color is dirty white, which
changes TO various tints of blush green, yell
low, or brown, as more or less of either pig
ment is forced up and rendered visible. The
animal is excessively sluggish aud defence
less, and lis power OF changing its color to
harmonize with surrounding objects is essen
tial to It's existence. H, too, as with the pup;e
OF papiliO Nfreus, cOlorS as scarlet or blue,
which do not occur in the i'm med ate envi-
ronment OF the animal, cannot be produced.
Somewhat similar changes OF color occur in
some praWDS and natish, ac cording to the
color of the bottom on which they rest. Tals
is very striking in the chameleon shrimp,
tMysts ChamRleOnl, which is gray when on
sand, but brown or green when among sea-
weed OF these two colOrS. Experiment shows,
however, that when blinded the change does
not occur, so that there, too, We probably
have voluntary or reflex sense &C lon.
Many cases are known among insects in
which the same species has different tint
according 10 its surroundings, this being
particularly marked in some South African
lOcusts, which correspond with the color OF
the soil wherever they are found; while sew
Cral caterpjllars which feed on two or more
plants vary in color accordingly. Several
such are quoted by Mr. r. Meldola, in pa
per on variable Protective Coloring In In
sects, Proceedings of the Geological Society
Of London, 1913, page 1857, and some OF them
may perhaps be due TO Photographic action
OF the reflected light In other cases, how
ever, IL has been shown that green chloro-
phyll remains unchanged in the tissues of
leaf eating insects, and being discernible
through the transparent integuments, pro-
cue the same color as that OF the food
plant.