Mower County transcript. [volume] (Lansing, Minn.) 1868-1915, 1890-08-27

is the Ichneumonidm, or Ichneumon
flies, including the BraconidB. These
are long, wasp-like insects, with long,
slender abdomens, and the females have
long ovipositors. In some cases these
hair-like ovipositors are three or four
inches long. Nearly all our injurious
insects have some species of Ichneumon
fly to prey upon them. Thus it that our
'curculio. our army worm, our Hessian
fly, as we'll as our cut-worms, etc., in
stead of being destructive every year,
are only occasionally sufficiently nu-
merous to awaken anxiety and alarm.
They are generally kept in check by
these vigilaut parasites. Occasionally
they get u brief advantage, perhaps
through some misfortune-possibys some
epidemic-among the parasites. and so
we say we have insect years. We might
better say years when our insect ene-
mics have eluded these vigilant para
sites. A few years ago many of our for
est trees were threatened with utter
ruin from bark louise. These para
sites commenced an attack upon the
pests, and in two years it was difficult
to find a single bark louise. The tiny
parasites had nearly exterminated a
very terrible insect pest with which we
could hardly cope unaided. In SINH
lar way have known the army-worm,
Aessian fly and wheat plant louise to be
overcome, and our valuable farm prod
ucts to be saved from destruction.
The Chalcid flies (Chalcidid@) so
nqnna6 fr0ro fhoir oofo11io oro11nr
or, are nearly or quite as serviceable as
are the lchneumon flies. They are
even more wasp-like in form They are
very small, and are easily known by
the very simple venation of their wings.
Their habits are like those of the Ich-
neumon flies.
The Chrysid flies (Chyrsididm) are
more of the form of sand flies than OF
wasps. They are usually bright-green
or blue, roll up when caught, and are
less common and so less important than
are those of the other two families.
Their habits are not unlike those of the
others.
The last family are the Proctotrupias
(Proctotrupid@). These are very mi
mute, and often parasitic on eggs of
other insects. The other day l found
on my currant bushes the eggs of some
very injurious bugs. To-day find that
from each egg came forth Proctotru-
pid fly. Thus an enemy is nipped in
the bud, or rather in the egg. These
flies are so very small that we do not
know how much good they do. 1t is
possible that they perform services
equal or superior to those of any of the
others.
We often destroy insects by the use
of poisons or otherwise, in the larva
and pupa state. Thus we use Buhach
to destroy the cabbage caterpillar, kero-
sene emulsion to exterminate aphides
and London-purple to overcome the
potato beetle. Close observation will
often detect in such insects celebration,
which indicates parasitism. When we
discover such attacks from parasites.
we should not destroy the pest, but
leave it to the parasites. They will de-
stroy it more cheaply than we can, and
in doing it. will preserve their lives for
failure conquests of the same desirable
nature. Again we can by shipping
parasitized insects often distribute the
parasites, and so send our blessing to
aid others. DIR. Lintner thus dis
tributed very minute Proctotrupid,
by sending eggs of the currant saw-fly
to various entomo]ogists of the several
States.
Oftentimes little knowledge of the
nature and work of parasites will
bring hope to the farmer. He will see
in these relief from threatened ruin.
Often it may lead him to SOW or plant
where otherwise he would have no
courage to do so. Thus study OF
these minute friends will amply re-
ward the practical man on his farm, or
in his garden and orchard.-A. j. Cook