Evening star., 1955-03-11
17-Yeur Locusts Build
Subterruneun Cities
Scientist Traces Active
Life of Creature Underground
By Thomos r. Henry

LIE OF SISutuIe OHuet9tVuhu
By Thomos R. Henry
Seventeen-year locusts build great
subterranean "cities" during their long
sojourn in the earth's depths.
Their years underground are by no
means q resting period-an episode OF
being buried alive. AL the time the
young locusts, in various transmuta-
tions, are busy building and eating.
This has just been reported in the
Journal of the Washington Academy OF
Sciences by DR.. E. A. Andrews. Johns
Hopkins University entomologist.
The eggs Of these strange insects are
laid during few weeks late in summer
inside twigs. From these come minute
nymphs which at once make their way
into the ground. There they shed their
shells from time to time and grow
rapidly. Their food is Juice sucked from
roots.
They make successive mud dwellings
attached to these roots. The largest
observed in this part Of the country
were 18 inches below the surface. Each
was q rough ball of earth about two
inches long and three-fourths Of an
inch wide. Each was lined on the in
side with smooth mud and contained
only one nymph. Every time an insect
moults and grows larger it must make
a new house.
Locusts Dig Upward.
Emerging from the last Of these
feeding chambers, DR.. Andrews says,
they dig upward rapidly and construct
a somewhat different type of dwelling.
Within these they rest for some weeks
before attaining wings and emerging
into the air.
These last dwellings," says DR.. An
drews, "have the advantage OF safety
some inches below the surface, along
with quick access to the surface when
the proper time comes. Each dwelling
has rounded ends above and below as
in previous subterranean shelters. but
these are connected by a long shaft
$50 to 800 millimeters approximately
7h to Is inches) long, although they
may be longer or much shorter.
In this shaft the nymph climbs close
to the surface, or falls rapidly to the
bottom to escape attack. The lining Of
the shaft is smooth mud few milli-
meters thick. The shafts are by no
means always straight or of uniform
diameter but may be sinuous and pre-
sent swollen regions"
In one area examined by DR.. An
drews he found that the topsoil was
such a mass of small stones and roots
that the insects actually must have
cut their way through roots. Large
objects often were avoided by a change
of direction.
THE chief implements used in max
ing cavities in the earth" DR.. Andrews
explains, "are the big first legs. Here.
as in other legs, the end segment Is
used chiefly in walking and may be
folded down when not needed. The
second segment from the tip is used
to pick off particles of earth. The third
segment is the largest and like power
full thumb acts with the opposing sec
ond as a forceps to pick up pellets Of
earth and small stones.
1.-THE minute particles picked loose
from the earth are raked together by
the tip segment to make pellet. which
the forceps can carry or shove into the
walls of the cavity. However, all parts
of the body may come into use. for
the hind legs and the abdomen may
help shove earth aside and the head
may carry earth plastered upon it. In
vertical tunnels the animal traces its
legs against the sides and, II disturbed,
relaxes and drops down.
More Spacious Quarters.
"The lower chamber in the last dwell
ing is large enough for the nymph to
turn about and commonly is dattened
below, as if to allow the nymph to rest
on fat surface. The dome or top OF
such dwellings comes remarkably near
the surface without breaking through.
leaving but few millimeters OF earth
until the time of the transformation
when the nymph digs its way out.
Examination of very many tubular
dwellings shows that closely neighbour
ing cavities do not interconnect. Each
has its own individual upper end and
exit and along its course avoids contact
with other dwellings though they often
run close together.
1.-THE last dwelling of the subter-
ranean nymph is not necessarily re-
stricted to the earth, but may be con-
tinued up into the air. Aerial extern
sions may, in fact, be abundant and are
in the form of turrets, towers, cones,
chimneys, huts and adobe houses. The
walls are dense mud, not natural soil.
externally more or less made of pellets
but internally lined with the same
smooth layer found in the underground
parts of the dwelling. Rarely. small
sticks or leaves are incorporated into
the walls.
1.-The aerial dwellings are built UP
rapidly in the night when nobody has
observed them"
The locust, because Of its building
activities, may do about as much good
as harm. Dr. Andrews says. Its towers
may weigh as much as 500 pounds per
acre and the earth is riddled with the
underground shafts. Thus the insects
plough" the soil after the fashion Of
earthworms.
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