Entomologist U. S. Department of Agriculture, and Curator Department of
Insects, U. S. National Museum.
There is an old German child's story of a little girl who being told
that if she could find a place to hide her first silver piece where
no eye could see her, and then dance round it three times, she would
have her wish. She sought everywhere for such a place, but always some
bird or squirrel or mouse or insect was near by, and even when she dug
beneath the ground, there too were little crawling creatures watching
her.
It may be said that this story was meant to show that animal life is
found almost everywhere, and certainly beneath the surface of the
ground there are hundreds of kinds of insects working steadily away
at their different occupations; for whatever disagreeable things you
may find to say about insects, you can never justly call them lazy.
The scriptures recognized this fact in the well-known command to the
sluggard, and the old nursery rhyme about the "busy bee" emphasizes the
same characteristic.
The truest underground insects are those which pass their entire lives
beneath the surface of the earth; which are born there, live and grow
and die without seeing the light of day. Such, for example, are the
true cave insects, a number of forms of which are found in the great
caverns in different parts of the world. Some of these insects feed
upon the vegetable molds and low forms of plant life found in caves;
others feed on dead animal matter and still others upon living insects.
Nearly all are of pale colors and are blind or nearly so, for they have
no use for eyes in the darkness. All are supposed to be descendants
of above-ground forms, which through many generations of life in the
darkness have lost their color and their power of sight. The genealogy
of these true cave forms may be guessed at with some certainty, for
we know insects which are only partly transformed in structure from
above-ground forms to true cave species. Such are certain beetles which
live in the catacombs of Paris, and certain other insects which have
been found in the old and deep burrows of the land tortoise in Florida.
But we do not have to go to caves to find many other true underground
insects. Rich, loose soil abounds in such creatures which live upon the
decaying vegetation (soil humus or vegetable mold) or upon one another.
The most abundant in numbers of individuals are the little spring-tails
or bristle-tails, minute creatures seldom more than a sixteenth of
an inch in length and which frequently swarm in the ground in such
numbers that the earth seems fairly alive. These little creatures are
by no means confined to the surface soil, but have been found in great
armies at a depth of six feet or more in stiff clay, which they have
penetrated by following the deeper rootlets of trees. Certain of these
little insects have also become so accustomed to this lightless life
that they have lost their eyes.
Other true underground insects are found in the nests of ants, where
they fill many different functions. They may be grouped, however as
follows: 1. Species which are fed by the ants and from which the ants
derive a benefit by eating a certain secretion of the insect. 2.
Species which are treated with indifference by the ants and which feed
upon the bodies of dead ants and other animal and vegetable debris to
be found in ants' nests. The ants are certainly not hostile to these
insects and evidently gain some unknown benefit from their presence.
3. Species which live among the ants for the purpose of killing and
feeding upon them. The first true ants' nest insect was only discovered
and studied at the beginning of this century, but since that time
hundreds of other species have been found, and a mere catalogue of
their names fills a book of over 200 pages.
Such insects are called "myrmecophilous species" or "ant lovers." The
man who has done the most in the study of these interesting creatures
is Dr. Wasmann, a Jesuit priest, who lives in Holland, and who has
devoted many years to this work, and a difficult task it has been! If
one digs into an anthill the inhabitants are at once alarmed and the
greatest confusion results, so that it is necessary to study them in
artificial nests in glass jars, or in some other way.
Although the most of these "ant-loving" insects are strictly
subterranean species, living their whole lives underground, the ants,
among which they live, do most of their foraging above ground, and thus
may be taken as typical of a second group of underground insects--those
which have their homes below ground for protection or concealment,
but which themselves live, at least part of the time, above ground.
Volumes have been written about the wonderful habits of ants, of
their community life, of the division of labor among them, of their
slave-making customs, of their courage, patriotism, and indefatigable
industry, of their highly developed instinct, which, in fact, becomes
real intelligence; so that almost everyone knows the main facts
about these wonderful little insects, and we can spend our time to
better advantage on those underground creatures about which there is
less general information. It will suffice to say that most ants have
their nests, consisting of tunnels and chambers, underground; that
there their queen lays her eggs and the young are carefully tended by
workers until they have reached the adult stage, and there the food is
stored for use in the winter months. There is a curious kind of ant
in the southwestern states and Mexico called the honey ant. Certain
individuals in a colony of these honey ants have enormously distended
stomachs and are fed by the other ants with a kind of grape sugar, or
honey, during the summer, as they hang suspended by their legs from the
roof of an underground chamber. When winter comes the other ants are
fed by these honey-bearers, which give put the stored-up honey from
their mouths drop by drop.
There is an interesting class of underground insects which, in their
early stages, hide in especially dug pits and lie in wait for their
prey, but which, when full grown, live above ground. Such are the
ant-lions and the tiger-beetles. The young ant-lion is a heavy-bodied,
clumsy-looking creature, with very long and sharp jaws, which digs for
itself a funnel-shaped pit in loose, dry sand, using its flat head
and jaws as a spade in digging. Then it hides itself at the bottom of
the pit, its body completely covered with the sand, and waits until
some unlucky little insect comes along and stumbles over the edge of
the hollow. The side of the hole is made at such an angle that the
sand slips down with the weight of even an ant and carries it towards
the open jaws of the ant-lion. Every struggle which the poor creature
makes to escape causes the sand to slide down faster, and the ant-lion
at the bottom jerks up a shower of sand with its head, which hastens
the miniature avalanche until the poor victim is within reach of the
powerful jaws and is devoured. The adult ant-lion is a beautiful,
gauzy-winged creature, not at all like its blood-thirsty larva.
The young tiger-beetle, or "doodle bug," as it is called in the South,
digs a straight burrow in hard soil, such a hole as would be made by
pushing a small lead pencil into the ground. This creature, like the
young ant-lion, has a clumsy body and powerful jaws, and on its back
are two projections armed with hooks which help it to climb up and
down in its burrow. It waits for its prey at the mouth of its hole,
which it closes with its head, thus making a sort of trap-door. The
little insect which steps upon this trap-door doesn't have time to say
its prayers before it is devoured by the voracious "doodle." Should
a large, strong insect walk over the burrow, the tiger-beetle larva
retreats precipitately to the bottom of its hole, which is sometimes
eighteen inches below the surface of the ground.
[Illustration: BEETLES
CHICAGO:
A. W. MUMFORD, PUBLISHER.
(CHLAENIUS (LIBIA (CICINDELLA (CICINDELLA (CICINDELLA (BRENTHOS
SERICEUS.) GRANDIS.) REPANDA.) GUTTETA.) LECONTEI.) MANTIS.)
(ALAUS (PASMACHUS (NECROPHORUS (DICAELUS
GARGOPS.) MARGINATUS) ORBICOLLIS.) PURPURATUS.)
CALOSOMA COTALPA CYCHRUS CALOSOMA
SCRUTATOR. LANIGERA. ANGUSTICOLLIE. CALIDUM.