Evening star., 1933-07-16

paper or by arranging pits into which the m
sect; tumble and cannot get out again.
There are three types Of active traps; plants
that add aggressive movement to the fy paper
arrang= =ment CT the first type Of passive traps,
plants thai snap shut their prey like steel
traps and plants that cage their prey.
OF the first of these five kinds Of insect traps
there are no examples easily reached In Amer
ica and they in any case the least inter-
esting of the insect traps.
The second type. however, the pitfaH trap,
is exceedingly common in some parts OF the
United States and Canada: and 1t is more
over the largest and most conspicuous of all
the carnvOrouS plants.
Plants belonging to this class are mostly 70
be found in the various genera of pitcner-plants.
Pitcher plants grow abundantly in bogs wher-
ever they occur in Canada. southwark through
the Grea: Lakes region and on down into ken-
lucky and Florida.
THE most striking thing about them even to
! the casual observer is the structure OF their
leaves These are followed into graceful vase
shaped pitchers with projecting flap down
one side to take the place Of the handle.
On the outstanding lip of the pitcher. and
again around z-ne within. there are multl~
tudes Of down pointing bristles. against whicn
no insect could possibly climb Below that Is
frantic insect feet to clutch. Below this again
is another bristle-set zone.
To make the trap the more attractive. near
the rim are many glands that secrete nectar,
like that of flower stuff of which insects
are notoriously fond.
More sinister is the purpose OF ether glands,
found abundantly farther down the pitcher.
They secrete a ferment or engine which
digests flesh just the pepsin OF our own
stomachs do.
Even more widespread than the pitcher
plants are the sundews. These plants grow on
wet soil almost all over the world, wherever
the chemical reaction is acid enough.
Most of them quite tiny plants-seldom
more than a couple Of inches across the whole
rosette of their tiny leaves, or more than that
height to the top of their little spire OF flowers.
Their leaves are either round paddles
shaped. and each leaf has a fringe OF project
ing little fingers around Its edge, and similar
fingers all over its surface. Each Of these tiny
fingers ends in a gland that secretes a sticky
stuff that holds any gnat or other tiny insect
that touches it as tang!efoot fly paper holds
n.y.
DUT the action Of the sundew trap is not tho
u merely passive action Of fly paper. When
one or more OF its ticky-tipped fingers catches
an insect, the insect naturally struggles Then
other fingers in the neighborhood stimulated
and each sets its sticky tip en- the lucklesa
victim. pinning him yet more firmly.
Perhaps most famous Of all the carnivoroua
plants is the Vensus aytrap. which is found
only in q limited area of the coastal plain of the
Carolinas. principally around the city of Will
mfngton, N. c.
The leaves Of this plant are perfect counter
parts of the steel traps used by fur trappers OF
the north. Each is divided at its outer end into
pair of semi-circular. bristle edged flaps that
hinge along the midrib and can close together
in as little time as half second.
Each of these flaps has three bristles on its
surface, which are the triggers of the trap.
When an insect alightS on leaf, a cater
pillar crawls up along the stem, it cannot avoid
touching these trigger bristles. When it touches
the first one. nothing happens. But second
or so later it touches another
The two stimuli. following one ON the other
within stated time, trip the internal mech
anism whatever it may be, and the two halves
fly together. The bristles the outer edges
interlock like the teeth of an alligator so that
there is no chance for even a small insect to
crawl out
And then the two halves Of the leaf, at first
concave with little space between them, press
together tightly, and the digestive glands pour
out their corroding juices
The Draqcback
flames do vou like going tn schooIo"