The Penn's Grove record., 1907-06-14
The Common House FLY.
Whence He Comes and WHITTIER He
Goes.
By HAROrD sOMERs, M, A,

The common house fly (Musea Do.
mestica) Is a creature Of such Hecre-
tive habits that although from the
very earliest times he has been with
lie, and the most ancient writer's have
mentioned and described him, still
very little was known Of his origin
and history.
1t remained for the eminent Bos-
ton biologist, DR.. A. 8. Packard, Ia
1873, to make known his origin, heb-
its and transformations from the egg
through the larva state with its two
changes to the pupa state, then to
the perfect fly.
Near the first Of August the female
lays about 120 eggs Of a dull gray
color, selecting fresh horse manure
In which to deposit her eggs, and so
secretes them that they are rarely
seen; it takes only t~wenty-four hours
for them to hatch into the first form
of larva, a white worm one-quarter
of an inch in length and one-tenth in
diameter. They feed on the decaying
matter of their environment, and two
changes or casting of skins occur be-
fore they turn into the pupa state;
this change comes very suddenly.
The entire period from the egg to the
pupa state is from three to four days.
II moist food is wanting when In this
condition they will eat each other
and thus decrease their number. Heat
and humidity greatly assist their de-
velopment, as upon careful computa-
ton each pound of manure around
stables and outhouses develops un-
der favorable conditions over 1000
flies. 1t is no wonder that where
these conditions exist we have such a
veritable harvest of the fly pest.
In the pupa state when the fly Is
about to emerge the end of the pupa
case splits off, making a hole through
which the fly pushes a portion of its
head, but here 1t seems to encounter
a difficulty; the pupa case is too
stiff and hard to pass through, but
nature comes to its assistance, and a
sort of bladder like substance forms
behind the head, which swells out
apparently filled with air; 1t acts as q
means of pushing away the pupa case
and releases the fly. When the fly
first energies 1t runs around with its
wings soft, small and baggy; it ii
pale and the colors are not set; its
head rapidly expands and the bladder
formation passes away-within a few
hours the wings grow and harden; II
is now a perfect fly.
The whole time from the deposit
ing of the egg to the perfect fly IL
not over ten days in duration. Many
persons who observe small flies in
midsummer suppose they are the
young, but such is not the case; they
are flies that are imperfectly nour.
ished in the larvae and pupae states
and do not attain full size; in fact
they are the dwarfs of their race. The
male fly differs from the female in
the front of the head between the
eyes, being at least one-third narrow.
er, though in size the female is rath-
er smaller.
Adult flies like most other crea2.
ures have parasites of minute size
that prey upon them; these can often
be seen as presenting small red
specks v e the body of the fly.
Another enemy in the form Of a
fungus often attacks the fly in the
early autumn. This makes it's art
pearance as a white swelling and the
white spores Of the disease can be
seen penetrating the body of the fly,
which it finally distends and rup-
lures.
The fly h~ibernates in winter, but
with his usual secretive habit it ia
very difficult to find him in his wintey
quarters. With the first chill Of au-
tumn the flies, feeling the cold, seek
temporary warmth in houses, and
clustering together form punches in
the of walls and other places.
They are then sluggish and not so &C.
tive as in the warm weather. How
ever, they do not make a permanent
stay indoors, but on the first mild,
sunny day seek the windows to get
hiding place. Many prefer to make
their homes in the roots of grass on
lawns, where they hide themselves so
effectually that the ice and snow of
winter does not destroy them in their
alternating state. If in the first
warm days of spring when the snow
is gone and the grass on the lawns
becomes dry and warm, long before
the yellow dandelion shows its head,
a close observer may see numbers of
flies crawling up on the grass to get
the welcome sunshine, their wings
standing out stiff and useless, but
they soon acquire the power of flight
in the warm rays of the sun. A great
many days, however, elapse before
they appear in the homes of men.
In recent years the medical profess
sion have demonstrated that while the
fly itself does not propagate disease,
it is one Of the most industrious car
riers of disease germs, which by con-
tact adhere to his feet, hairy legs and
body, distributing them to innocent
victims.
If every h~ousekeeper could know
all these interesting facts, which have
never before been brought to their
attention. they would realize the i'm
portance of securing the very best fly
exterminator.