The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1899-08-09

perfect insect. In like manner IN the
adult, scales exhibiting the more print
tive colors are of simple structure ana
ARE replaced in phylogeny by scales of
more complex structure and more spe-
cialized tint And this shows, he adds,
how far color changes are from being
superficial, and how intimately they
are connected with the other character
istics of the animal.
Equal activity is being shown by
chemico- biologists in the study of the
coloring matter of flowers. 1t is now
held that nearly all blue and red pig
mentS originate from tannin: in other
words, tannin constitutes the chromo-
gen of the red and blue floral pigments.
Keegan, in a recent article reviewing
the subject, shows that the circum-
stances which created or influenced the
particular tint of flowers, is first chem
ical (the presence of quercetin in the
form of ruth. etc, in the corolla; and,
second, physiological, i. e, the pos
session by the corolla of energetic res
piratory and transpiratory functions,
with the result that the substances
contained in its cells undergo an OK
ldation, more or less vigorous and COM
plete."
In this explanation of the cause of
the differences of color in flowers We
hear nothing of natural selection as an
active cause. Extreme Darwinians,
however, like Wallace and others, in
Sist that in the case of animals the
colors are produced by natural selec-
ton" But in reality natural selection
is not an efficient. initiative cause; it
only expresses the results of a series of
causes, these being the effects of
changes of temperature, light, etc.
AS originally stated by Hagen in his
able naner On the cOlOrc Of inSaqtS their
hues are probably due to light and air.
while the other factors are changes in
heat and cold, moisture and dryness, as
well as in the structure of the scales in
those insects possessing them.
The more we examine the subject the
more clearly ii is seen that we must
depend on the action of these primary
factors in the evolution of life. In the
case of polar animals, their white colors
are evidently due to cold More black
moths and butterflies occur in noun
famous regions than elsewhere, and
this mechanism is due to cold and moist
ure. The faded-out appearance of des-
ert animals is due to dryness, for ami
mails which prey on others as well as
those preyed upon are of the same gen
eral hue, as in the case of many in
sects, birds and reptiles. while the lion
is tawny yellow, like the sands of waste
places. The dry heat of the desert does
not bring out gay colors. but in the
semi-tropical regions adjoining them,
where there is both heat and moisture.
the bird and insect life is richly colored
When green grasshOppers change to
pink or yellow, as may happen in sum-
mer, but more usually in autumn. the
cause appears to be a lower tempera-
ture.
There are still many unexplained
problems in the matter of protective
mimicry. but we are and have been for
many years past convinced that the
causes of the origin of color and of
color variation are general and per-
vasive, both chemical and physiolog-
ical, and due primarily to changes in
the environment. while individual cases
may be due to biological environment
Or to the struggle for existence. Still
the explanation of certain wonderful
cases of mimicry is inadequate and
needs further study