The Denison review. [volume] (Denison, Iowa) 1867-current, 1898-09-16


= Mystery-How the Ely Walks en-
Ceiling-His Wonderful Feet.
The humble househy is one of the
oldes and always has l1enn one of the
most distinguished of insects. He was
worshiped by the ancients and placed
as a constellation in the heavens The
Philistines sacrificed to Beelzebub as
god of flies and the Cyreneans to
Achor The Greeks offered an OK every
year to Zeus Apomyios in honor Of the
god of flies, and the Romans sacrificed
yearly in the temple of Heracles Vic
tor, in Rome. The Syrians too, tried
to appease the troublesome god. The
Koran of the Mohammedans promised
that "all flies shall perish except one,
and that is the bee fly
Despite their antiquity, flies are still
something Of a mystery, and it was not
until 1884 that Dr. J. E. Rombout,
French entomologist, discovered and adj
vocated the correct theory Of how a
bout proved that the fly clings to a
smooth surface by capillary force, the
| molecular action between solid and
liquid substances. The insects feet are
covered with many thousands of very
fine hairs, each of which terminates in
bulb Through these hairs runs thin
liquid that sweeps through in tiny
drop at the end. When several thou
sands Of these drops have been fastened
to a window pane or ceiling, there is
no difficulty at all for the fly to hang
on and no difficulty for him to release
himself instantaneonsly.
| This is the theory of Rombout, OBJ
tanned after some very fine calculations.
| A once popular idea was that the feet
Of the fly, being cup shaped, enabled
him through what is called suction to
cling to the ceiling, but Blackwell put
flies in glass vacuum, where they
climbed the sides as easily as in the
open air. Hooke next tried to prove
that the fluid the feet Of the fly sent
out was viscous and held the insect to
the surface like mucilage. This theory
was exploded by Rolftbout, who proved
that the fluid was not viscous. And if
it We're, said he, it would be absurd to
suppose that fly, after resting in one
position for an hour and giving the
thick liquid time to harden, could re-
lease himself instantaneously when
alarmed.
Then Rombout set about formulating
his own theory. He examined the tracks
of flies on a window pane, and the idea
Of capillary force impressed him. He
dipped the end of a hair in oil of olives
and succeeded in suspending the hair
from clean glass pane. Water brought
the same result as oil Of olives. By a
series of fine calculations Rombout
found that fly could walk upward on
vertical glass pane supporting an in
crease over his own weight Of 900 of a
grain. He then weighted down flies
with paper attached to their backs and
found by experiment that his reckoning
was correct.
Rombout, in the course of his expert
ments, discovered other very interesting
things about the fly. Each of the two
wings Of the insect is provided with
hairs on the underside that serve as a
fine brush to clean the feet When fly
rubs its legs, he is not always washing
his body, but is often removing the dust
particles from the hair in his feet that
the fluid may run better. The feet must
be kept clean, or the fly cannot cling to
surface He finds it impossible to
walk across pane covered with dust,
and oily surfaces cause the liquid from
his feet to run together, so that he is
apt to slip.
Under the wings of fly is pair of
balancers, little threads that terminate
each in an oval button When the fly is
on the wing these buttons expand and
guide the fight. A fly has no lungs,
but breathes by spiracles, or breathing
pores, that lie open all over his body
and connect with an intricate system of
air tubes. These spiracles are protected
from the dust by networks Of fine. flmy
fibers that look something like exquisite
lace work.
The chief value Of the fly lies in his
scavenging qualities. Indeed some
scientists say that without his assist
ance man would not be able to live in
the temperate zone. The fly feeds on
both liquids and solids His mouth is
shaped something like pump, and he
sips perspiration and saliva, his favor
lite foods, through fine and cunning
tubes. Solids he reduces to liquids Le-
fore he swallows them by process OF
secretion. He is voracious eater 1t
has been estimated by scientists that a
fly can multiply himself 900 times every
"a hours Each new born fly becomes
full grown in four or five days.
Nature has provided we'll for the fly
in his powers of flight and ability tc
escape from danger. He is supplied
with 1000 separate eyes, that never
sleep, and can look either in front or be.
hind. Each eye is separate and Of pecul-
lar construction, shaped like a hexagon.
When alarmed, the fly leaps swiftly
from his resting place into the air.