The citizen. (Frederick City, Md.) 1895-1923, 1911-05-19


anything out side of an exact science
and that is that they have never been disputed
There is a unanimity of sentiment surrounding the
onslaught on the house fly which ought either
to receive our highest Endorsement or arouse our
darkest suspicion, Just the spirit is apt to
incline
The house fly proper Musca domestica, of the
order of the Diptera, is a graysh fly with mouth
formed for sucking up liquid substances.
1t has proboscs something like the trunk Of
elephant in miniature, and it's feet are termin
ated each by pair of claws between which are
more or less membranous arolia or plantulae
which climb polished surfaces and also pulvi
lus cushion. 1t does not bite for that function
is reserved for stable fly which resembles it so
closely as to deceive anybody but entomo
ogist Neither does it die upon the window pane
surrounded by the fungous efhorescence so ia
miliar to the disguised housewife. That is the
habit of the cluster fly which is somewhat larger
than the house fly, with dark-colored, smooth
abdomen, and sluggish disposition
Several other species bear superficial like
ness to the true house fly and are more or less
mistaken for it. All are so inconsderate IN num-
Der in comparison to the common pest fowever
that they may safely be disregarded in the dis
cussion
The great breeding place Of the house fly is
horse manure. 1t will it is true, thrive to some
extent in other sorts of decaying animal and vege
table matter but its partially for the stable ref
use is so great that the vast proportion of its off
spring may be considered as originating in that
substance.
The fly lays its eggs upon the manure, which
is its favorite arval flood, and a generation may
be bred in from ten to fourteen days, according to
the climate. There may be dozen generations
in a summer An individual fly will average 100
eggs, and when the prevalence of horse manure
Is taken into consideration its widespread app-
cation to farm lands in the way of fertilizer
its presence in piles in city stables, its
use upon lawns and suburban gardens, the posi-
bilities in the propagation of the fly Will be read
fly seen to be past computation. 1t is even calcu-
lated that single fly, laying 1870 eggs, will pro
duce a progeny amounting to sextillions in one
season This probably does not take into con
sideration accidents which operate greatly to re-
duce the supply.
Some experiments have been made with view
to calculating the number in which house-hy
larvae occur in manure, but no general average
can be struck Twelve hundred house flies to the
pound of manure is the result of one observation.
Another showed 200 puparia in less than cubic
inch. Yet perhaps no larvae can be found in
the greater part of manure piles,
Because of his habits the house fly is walk
ing arsenal of bacilli. The old notion that he
was valuable a scavenger is untrue He will
prey on garbage and carry it away as part and
parcel of his tissue, but he does not kill the germ
he absorbes 1t has been proved that the bacteria
are not only taken into the fly and pass through
its body without any loss of their active proper
ties but also that in all probability they multi
ply during their sojourn there.
These germs are deposited upon foodstuffs and
eating utensils pass into the human economy in
spite of ordinary care, and if they of a malev-
olent type and the system which takes them in
is not strong enough to resist their action, dis
tress disease and death are apt to follow in their
wake In addition, the fly also disseminates
germs by carrying them upon his body, the cush-
ions of his feet and his wings
Through the researches of W. NJ Eaton and g.
J. Mason it has been found that "the numbers of
bacteria on a single fly may range all the way
from $50 to 66O0OOO' No general average can be
struck. few million more less will lsake no
difference in the general result.
Because of its prevalence and its familiar asso
citation with man. Musca domestica has exception
al opportunities to distribute disease-breedng bac
terra where they will do the most harm A
tain genus of mosquito disseminates malaria, but
the mosquito thrives only in localities especially
favorable to his propagation There is good rea