Noticing a statement made by Mr. J. A. Lintner, to the effect that the
Persian insect powder would probably prove unavailing as a remedy
against the ravages of the new carpet beetle (_Anthrenus_), W. L.
Carpenter, of the U.S.A., was led to institute some experiments with
this well known insecticide, the results of which he communicates to
the current number of the _Naturalist_. A small quantity of the powder
was introduced, on the point of a penknife, under a tumbler beneath
which various insects were consecutively confined. The movements of
the insects brought them in contact with the poison, which readily
adhered to their body; in endeavoring to remove it from their
appendages a few particles would be carried to the mouth and thence to
the stomach, with fatal effect. The results were briefly thus: A honey
bee became helpless in 15 minutes; a mad wasp in 8 minutes; a small
ant in 5 minutes; a large butterfly resisted the effects for over an
hour, and apparently recovered, but died the next day; a house-fly
became helpless in 10 minutes; a mosquito in 15; and a flea in 3
minutes. In experimenting on beetles, an insect was secured as nearly
the size of the carpet beetle as could be found. It was easily
affected, and became helpless in 12 minutes.
In these, and experiments with various other insects, the scent from
the powder did not produce any bad effect on those subjected to its
odor where actual contact was not possible; but when carried to the
mandibles the effect was to produce complete paralysis of the motor
nerves. The experiments prove that all insects having open mouth parts
are peculiarly susceptible to this popular insecticide. As a result,
the writer does not hesitate to recommend the powder to housekeepers
as an infallible agent in destroying the carpet beetle and preventing
its ravages. The Persian insect powder liberally sprinkled upon the
floor before putting down a carpet, and afterward freely placed around
the edges, and never swept away, will suffice to preserve a large
sized carpet. No ill effects from its use need be feared by the
householder, since the drug is poisonous to no kinds of animals except
insects.
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