St. Tammany farmer. [volume] (Covington, La.) 1874-current, 1915-01-09
THE FLIGHT OF FLIES.

One of the problems that has arisen
in connection with the part played
by insects as carriers of disease con-
Germs the distance which they may be
able to carry from one locality to
another. This has frequently been
considered in this country in connec-
ton with mosquitoes which are re-
sponsible for the prevalence OF ma
laria. With their breeding places
known, it has become desirable in
some cases t oascertain what the
range of their activities might be in
respect to the territory which can be
covered by insects. It has been
learned that mosquitoes which In
habit salt marshes near the seacoast
may be found inland at distance
as great as three miles. ..
Far less appears to be known with
regard to the migrations Of the COM
mon house-hy, an insect charged with
responsibility of typhoid fever and
other infectious diseases. A series
Of studies conducted in Cambridge,
England, on the range of the flight of
flies Of this species has been made
the subject of report to the Local
Government Board on Public Health
and Medical Subjects. Upward of
$4,000 flies were liberated, under va
rious meteorologic conditions, from
the medical buildings at Cambridge.
OF these insects, colored for adentif1
cation, 191 were recovered. The re-
suits showed that house-flies tend to
travel either against or across the
al
ed may be determined either directly
and by the action Of the wind, OF
directly owing to the flies being at
tracted by odors from food. A point
in favor Of this supposition is the ma
ture of the station at which flies were
recovered after they had travelled any
distance. These comprised a butch
er's shop, public houses and a res
taurant, all of which gave of odors
that are VIGOROUSLY attractive to
flies. The chief conditions favoring
the dispersal of flies are fine weather
and warm temperature. The ma
ture of the locality is another con-
siderable factor, because in towns
flies do not travel as far as in open
country, probably due to the food
and shelter afforded by the houses.
With regard to the altitude Of the
point Of liberation, flies set free from
the roof tended to dispense slightly
better than those liberated from the
ground, but the differences are not
very considerable. It has been OBJ
served, with regard to the vertical
flight Of the house-fy, that it may
mount diroo<lv r,puopd ~ . hn;~h< ~
forty-five feet or more. The time
Of day appears to influence the dis
persal of the insects, as, apparently,
when set free in the afternoon they
do not scatter so we'll as when lib
Grated in the morning.
The maximum flight observed in
the thickly housed localities in Cam
bridge was about a quarter of mile.
In one case, where a part of the dis
lance was q ross open fenland, q
flight OF ITO yards was noted. In
experiments conducted in Cook Coun-
ty. Illinois, by s. A. Forbes, flies were
trapped and, after being sprayed with
a chemical solution for recognition,
were liberated from hospital in that
district. They too were recovered at
distances ranging up to a quarter Of
q mile from the point of liberation.
The distance flies may travel to reach
dwellings is controlled by circum-
stances. Almost any reasonable dis
lance may be covered by the fly under
compulsion to reach food and shelter.
COAL MINING IN THE SOUTHERN
STATES