The Topeka state journal. [volume] (Topeka, Kansas) 1892-1980, 1914-12-30
THE FLIGHT OF FLIES.


One of the problems that has arisen
in connection with the part played by
insects as carriers Of disease concerns
the distance which they may be able
to travel from one locality to another.
This has frequently been considered
In this country in connection with
mosquitoes which are responsible for
the prevalence Of malaria. With
their breeding places known. it has
become desirable in some cases to as
certain what the range OF their activi-
ties might be in respect to the terri
tory which can be covered by insects.
1t has been learned that mosquitoes
which inhabit salt marshes near the
seacoast may be found inland at Q dis
lance as great as three miles.
Far less appears to be known with
regard to the migrations of the COM
mon house fly, an insect charged with
responsibility for typhoid fever and
other infectious diseases. A series Of
studies conducted in Cambridge, Eng
land, on the range Of the flight Of
flies Of this species has been made the
subject Of a report to the local gov
eminent board on public health and
medical buildings at Cambridge. OF
flies were liberated. under various
meteorologic conditions. from the
medical buildings at Cambridge. OF
these insects. colored for Identified
ton, 1911 were recovered. The results
showed that house flies tend to travel
either against or across the wind. The
actual direction followed may be de-
termined either directly and by the
action OF the wind. or indirectly owing
to the flies being attracted by odors
from food. A point in favor of this
superstition is the nature of the sta
ton at which flies were recovered
after they had travelled any distance.
These comprised a butchers shop.
public houses and a restaurant, all Of
which gave off odors that are notori-
ously attractive to flies. The chief
conditions favoring the dispersal of
flies are fine weather and a warm
temperature. The nature of the To-
cality is another considerable 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 dis
perse slightly better than those hber-
ated from the ground, but the differ
ences are not very considerable. 1t
has been observed, with regard to the
vertical flight of the house fly, that it
may amount almost directly upward
to a height Of forty-five feet or more.
The time of day appears to influence
the dispersal Of the insects, as, appar-
emily, when set free in the afternoon
they do not scatter SO we'll as when
liberated 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 across open fenland. a
flight of TO yards was noted. In ex-
periments conducted in Cook county,
Illinois, by S. A. Forbes, flies were
trapped and, after being sprayed with
a chemical solution for recognition,
were liberated from q hospital in that
district. They too were recovered at
distances ranging up to a quarter of a
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 I'M
der compulsion to reach food and
shelter.