he free transmission of
sound vibrations.

I am well aware of the fact that in considering these organs to be the
ears of flies, I antagonize Lee and others who consider them olfactory
in character.[20] The position I take in regard to these organs is,
however, a tenable one, and one that cannot easily be overthrown.

[20] Bolles Lee, _Les Balanciers des Dipteres_; quoted also by
Lubbock, _Senses, Instincts_, etc., pp. 110, 111.

The ears of Lepidoptera (butterflies) are situated in their antennae. This
fact has been clearly demonstrated by Lubbock, Graber, Leydig, and Wolff.
Newport has made an especially exhaustive study of the antennae of insects;
and he, too, places the organs of audition in these appendages.[21] But in
Coleoptera my experiments and microscopical researches compel me to
assert that I differ somewhat from the conclusions of the above-mentioned
authorities. These gentlemen locate the ears of beetles also in their
antennae. Lubbock bases his conclusions on an experiment of Will--an
experiment which, if it had been carried a little further, would have
demonstrated the fact that the ears of beetles are not in their antennae,
but are, on the contrary, in their maxillary palpi.

[21] Newport, _The Antennae of Insects_, Entomol. Society, Vol. II.

Will put a female Cerambyx beetle into a box, which he placed on a
table; he then put a male Cerambyx on the table, some four inches from
the box. When he touched the female she began to chirrup, whereupon the
male turned his antennae toward the box, "as if to determine from which
direction the sound came, and then marched straight toward the female."
Will concluded from this that the ears of the beetle were located in its
antennae.[22]

[22] Will, _Das Geschmacksorgen der Insecten_, Wiss. Zool.; quoted
also by Lubbock, _Senses, Instincts_, etc., p. 96.

Seeing that Will's experiment as described by him was incomplete, I took
a pair of beetles belonging to the same family (genus _Prionus_), and
determined the true location of their ears by a system of rigid
exclusion. These beetles, when irritated, make a squeaking chirrup by
rubbing together the prothorax and mesothorax.

When I irritated the female she began to chirrup, and the male
immediately turned toward the small paper box in which she was confined.
I then removed the antennae of the male, and again made the female
stridulate; the male heard her, and at once crawled toward her, although
h