The Yakima herald. [volume] (North Yakima, W.T. [Wash.]) 1889-1914, 1909-09-08


insect. Curiously enough, too, just as
in the case of the plant, it is the blue
component of the light that is most eff
fective. Too bright a light, however,
works the other way. The insect be-
comes negatively phototropic," heads
away from the light. and, if il flies at
all, flies, on the whole, toward the
darker regions. In general, too, each
sort of insect has its special place
where it draws the line between the
moderate light toward which it turns
its head, and the excessive light on
which it turns it's back. With most in
scots, also, the point at which occurs
the change from positive photoropism
to negative depends on temperature,
and various other
changeable conditions.
Those terribly scientific people. the
Germans, are utilizing this common
phototropism of insects to STAY oh
5ectionable moths by the ton. They
set light, of just the right size and
brightness where it will attract the
moths into the sphere of infiuen ,e of
vacuum fan. After that, nothing re-
mains to be said concerning the
moths
A Scientific Device for Kidding the
House of Flies.
The common fly is much less sensi-
tive to light than the moth; neverthe-
less, he is sufficiently phototropic to
be vulnerable on that side. Every
housekeeper has noticed that on GER
tain cloudy days her flies collect on
the screens and window-panes, as if
they were trying to get out. 1t is a
good plan to let them. The dim illu-
minated inside the house has made
them uncommonly sensitive to ligh..
while outside the light is not so bright
that their phototropism becomes neg
alive.
In fact, one can usually, after a
little experience, no matter what the
weather, clear a room of flies by the
obvious device of opening the window
and letting them fly out. The light in
the room must be dim, but not so dim
as to remove the stimulus to move"
ment There should be a single bright
opening, so that all the light shall
come from one region. That single
opening should usually be where there
is shade outside, that the light there
may not be too bright. These con-
ditions fulfilled. the flies can no more
stay in the room than a house plant
can grow away from the window.
Or, If one fears to leave a window
in fiy-time,-this certainly
does take nerve or an uncommon faith
in science,-it is a good plan to adjust
the light to bring the flies toward the
window, and equip the bright part of
the room with fly-paper. This device,
combined with an odoriferous bait on
the paper in the bright area, Is often
most effective. The tendency to head
toward a smell is also of the nature
of a tropism. With the two tropisms
working together, the problem of free
will for the fly becomes purely acad-
emic.
There is really a great field for in
ventions which shall utilize the trop-
isms of too-abundant insects. 1t would
be well worth while for the possessOr
of room infested with carpet m oths
to experiment with an electric light
of one or two candle-power set over
night in the middle of sheet of
"tanglefoot." So far as I know, only
one such invention has been aimed
specifically at the house-fy. This is a
contrivance invented by the late Ed
ward Atkinson, of Aladdin oven fame
Atkinson" he used to be
called by persons who resented his at
tempts ito ameliorate the condition
of the eating classes
Sending the Flies Down Fly Escape
Atkinson's "fy escape" is a window,
preferably on the east side of the
kitchen, which has in it's lower half a
single large pane set flush with the
sash on the side toward the room.
Thus the lower part of the window,
sash and glass together is a single
unbroken surface, on which a fly can
crawl unobstructed. The usual posi-
ton of the sashes, moreover, is re-
down inside the lower.
The trap is set by dropping the up
per sash six or eight inches and draw
ing the upper sash six or eight inches
and drawing the curtain to it's lower
edge. The positively phototropic flies
in the dim light of early morning are
obliged to go to the window. But flies
are also to a marked degree negative
ly geotropic, that is to say, they come
to rest on a vertical surface head up.
When they crawl, therefore, they
crawl upward. Crawling upward, they
crawl between the two sashes and out
of doors, where they belong. The in
ventor of the 'hy escape" had unlim-
tied faith in it; but the general run
of cooks do not seem to be well
ground in animal psychology.
There is, theoretically, still simp-
Ter form of the "fy escape"-though
unfortunately, it can be used only I'M
der special conditions. The fly's eye
sight is extraordinarily bad, so bad
that if he looks at an ordinary screen
against a dark background he see it
as a continuous SURFACE; but II he
looks at the screen against the light
he does not see it at all. This is true
even of screen with a half-inch
mesh. If, then, a room with windows
on one side only were screened with
coarse netting, the flies would go out
freely toward the light. but come in
only as they blundered through. A
fine screen does noticeably check the
draft through window. and one car