Wauwatosa news. [volume] (Wauwatosa, Wis.) 1900-1948, 1902-10-04
QUEER WAYS OF INSECTS.
Protective Resemblance and Warning
Colors.

ColOrs.
At the Royal Institution recently Prof
T. =. PoultOn delivered an address OF
Protective Resemblance and Warning
Colors in Insects" this being one of two
discourses designed to show what prog
ress has been made in a fascinating field
of research since fifteen years ago he
lectured on the same subject in the same
hall.
Fish and other animals tend to be dark
on the upper side of the body and light
on the under side; it was long before
naturalists discovered the reason for TINS.
They know now-and every visitor to the
Natural History Museum knows what
they know-that is, if he has caught the
significance of \. ii. Thayer's model Of
the visible and invisible duck. Mr.. Thay-
er has painted the upper part Of one Of
the bird forms of much the same color
as the background, and he has painted
the under part considerably lighter.
That is the invisible duck. In the other
case, he has painted the bird form the
same color all over, and behold, the un-
der side appears much darker than the
upper with the result that the duck Is
most conspicuous. This model thus
serves as an admirable illustration of
natures intention in making dOrsal sur
faces so much darker than ventral sur
faces
The earth is lit from above, and it was
necessary--if animals were not to be eX-
tremely c0nspicuOus-that the inevitable
shadows should be connected. As Prof.
Poulton put it, 1.-The form painted light
below and dark above, with connecting
gradatinHs, looks visionary and ghOstlike,
as wild animals always appear in ma
ture" He was on the track Of that dis
covery in 1887, when he perceived that
the hight hairs and flesh projections OF
the caterpillar of the birthstone moth
were intended, by neutralizng the shaG-
ow, to Obliterate the creatures line of
contact with the hawthorn bark. But 10
Mr. Thayer is due the credit of seeing
the wide application Of the principle IN
contemplating that very great and CON
vincing discovery" the professor feels
inclined to echo the remark which uuX-
ley made on reading THE Origin Of
Species, How stupid of one not to
have thought of it before
One day naturalist out collecting in
British East Africa espied what he took
TO be n fine fOXglove He picked the
stalk whereupon the great doweriets at
the top and the red flowers in the middle
all ileW away, leaving only the seed pods
below. which turned out to be fulfilled
larvae. Between the green and the red
homoptcra-for such they were-thcrp
was no difference of age, kind or sex.
Some were green and some were red for
no other reason than that the colony. by
grouping themselves in the manner midi
Gated, might be disguised as a flower
spike, and so escape the notice of enc
mics. Other homOptera of East Africa
Prof. P0ulton has since discovered
pass themselves off as flowers on hori-
2onta branches.
In breeding geomctrae the lecturer has
found that those placed on Turkish oak
assume corresponding black hue. those
placed on dead ivy leaves become yellow.
while those placed on paper spills go
white. At the 1892 meeting of the Brit.
ish association gentleman came for
ward ant. announced that he had .discov-
cred sonN quefcifoiia in lichen, SO the
lecturer afterward placed some of the
larvae on liehen, and they became gray
and mottled. But ne could not make
any of them green, the explanation be.
ing that in nature they do not rest on
green leaves or stalks.
Beetles also vary their colors in har
mony with their surroundings. 4 it'll,
common wecvil is ruddy in the red sane
of Bears Hin, Deal, aud gray in tn,
gray ground of ShOtuver Hill, Oxford
Again, the professor found certain
grasshopper brown in one part of Helg0
land and green in another. both color
corresponding with local hues. Londol
Post