Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1873-07-10

raise itself an inch from the ground. The
ball and the insect were afterwards
weighed, the latter having been
made insensible by the fumes of
ether. Crickets of the larger kind raised
about one and half their own weight;
the smaller ones three or four times their
weight. The grasshopper differs from the
cricket in having longer and thinner legs;
the green variety weighing about two and
half grammes, can only raise weight
equal to its own, confirming the law that
the muscular force of insects increases as
their size diminishes. When allowed to
jump freely, crickets describe curve iii
the air similar to all projectiles. 1t is
curious that the amplitude of the spring is
the same for the large and smaller kinds
alike. This result was foreseen by the
celebrated naturalist, Strauss Durckheim.
In his work on THE Comparative Anat-
omy of Articulated Animals" he estab-
fishes the point that two animals of SINH
lar form, but of different dimensions, will
Jump the same height above the point
where lies their center of gravity at the
moment when they quit the soil. He
takes as an example the cat and the tiger,
and adds that the same conclusion is APP
plicable to crickets and grasshOppers.
The principle which serves as a basis for
this theory is, that the motive power OF
animals increases with the section and not
with the volume Of the muscles. 1t de-
ponds only on the number of
fbres of which the muscles are
composed; from whence it follows
that it ought to be in proportion to
the surface of the section Of these organs,
whilst the weight of the animal is proper
tional to their volume. The weight aug
ments more rapidly than the motive
power, and the relation between this
weight and this force becomes the more
unfavOrable as the animal is larger Other
naturalists who agree to this as whole
do not consider it to be an absolute gener-
al law. Among the insects that dig or
burrow in the ground, a different plan
was tried to see their power of pushing
forwards. They were placed in card
board tube, which had been blackened
and made rough for the feet; at one end a
transparent plate of glass was fixed to a
horizontal level Perceiving the light be
fore it through the plate which barred its
exit, the insect when excited pushes with
all its strength; the plate gives way, the
lever turns, and raises at its other extrem-
ity the balance, which is attached by a
pulley, and into which the sand is poured
as before. In this way the oryctes,
weighing about torty-six grains
pushed three or four times
its own weight, whilst the little
onthophagus moved eighty or ninety
times that amount. The experiments in
that insects employ much less muscular
force in that way than in drawing or push
ing; perhaps it is that, unlike birds, they
MT cd ia oi,rht
through the air A ball of soft wax of a
weight little superior to what the insect
might be expected to bear, was fastened
round its body, and it was tried as to
whether it could support this in the air:
if it fell, the size was diminished. Among
various insects belonging to the five orders
OF COleOptcra (bectles), it was found that
they could raise from One-sixth to double
their own weight; the common fly could
manage triple that amount. Yet the flight
OF insects is so rapid that some can dis
lance the swallows that pursue them, and
certain kinds Of flies are said to be able to
pass race horse or a locomotive going at
full speed. If we inquire why the smaller
species are the stronger, the answer may
be that their way of life necessitates
it. Thus the hardness of the soil
is the same to all the burrowers
the grains of sand which the larger
easily displaoo IuChs to the small
er ones; and, comparing them with ami
mails, the mole and the rabbit require
much less strength to force a passage than
the ant. The prodigious leaps of the
cricket, the locust, and the grasshopper
would, in the same proportion, make a
lion spring over half a mile. Not less
surprising is the power of destruction in
certain classes: the termites have under
mined whole towns which are now sus-
pended over catacombs. Such is the case
with Valencia, in New Granada; La
Rochelle is menaced by the same fate.
The Larvae or the sireX pierce through balls
| Of lead with their mandibles. During
| the Crimean War; packets of cartouches
| were found the conical balls of which
| were perforated in various parts. The
little African ant can raise mounds of clay
five yards high, and of such solidity that
| the wild cattle stand on them to explore
the horizon. Such edifices are thousands
| of times larger than their architects,
whilst the pyramid of Cheops is but
ninety times the height of man
Another subject which has engaged the
attention of naturalists of late is the
strict relation which exists between the
habits, manners, and mode of life in in
sects with the conformation of their
organs. Mr.. Darwin has acknowledged the
organic adaptation Of species to the con-
dition Of existence; but he thinks that,
owing to their want of exercise on one
side and natural selection on the other,
| these organs may undergo deep and hered-
itary notifications. Thus he explains the
want of wings in many coleopterous in
sectS which inhabit the island of Madeira
they lose the habit of flying, because, if
| they used ii, The wind would carry them
| away into the sea, and the race would
soon disappear. Thus, winged insects
made for flight can transform themselves,
in time into walkers or swimmers.
If we consider the locomotive organs of
insects, it is easy to see that broad mem
bers which can be converted into oars be-
long to swimmers; when they are short
and indented, they are to be used like
shovels and pickaxes by the burrowing
tribes. Though the mouths of insects are
formed with the same number of appli-
ances, yet they are adapted to the cond-
tons Of each species. BY examining one
or two parts Of the mouth of larva, a
naturalist can discover the food it lives
upon and the way in which it
partakes of it. Thus, if two cater
pillars of different kinds live on the same
plant, one may attack the leaves from
the edge, the other will perhaps eat the
flower-bud. These habits are recognized
by indubitabe signs when the lips and
mandibles are examined By similar
means, the inspection of the foot will de
eide whether the insect walks on leaves
orr l he 4 ),,c tn - ~