de of
repose.

The right wing-cover overlaps the left. Its inner edge carries, on the
under side, near the base, a callosity from which five radiating
nervures proceed; two of them upwards and two downwards, while the fifth
runs approximately at right angles to these. This last nervure, which is
of a slightly reddish hue, is the fundamental element of the musical
device; it is, in short, the bow, the fiddlestick, as is proved by the
fine notches which run across it. The rest of the wing-cover shows a few
more nervures of less importance, which hold the membrane stretched
tight, but do not form part of the friction apparatus.

The left or lower wing-cover is of similar structure, with the
difference that the bow, the callosity, and the nervures occupy the
upper face. It will be found that the two bows--that is, the toothed or
indented nervures--cross one another obliquely.

When the note has its full volume, the wing-covers are well raised above
the body like a wide gauzy sail, only touching along the internal edges.
The two bows, the toothed nervures, engage obliquely one with the other,
and their mutual friction causes the sonorous vibration of the two
stretched membranes.

[Illustration: THE ITALIAN CRICKET.]

The sound can be modified accordingly as the strokes of each bow bear
upon the callosity, which is itself serrated or wrinkled, or on one of
the four smooth radiating nervures. Thus in part are explained the
illusions produced by a sound which seems to come first from one point,
then from another, when the timid insect is alarmed.

The production of loud or soft resounding or muffled notes, which gives
the illusion of distance, the principal element in the art of the
ventriloquist, has another and easily discovered source. To produce the
loud, open sounds the wing-covers are fully lifted; to produce the
muted, muffled notes they are lowered. When lowered their outer edges
press more or less lightly on the soft flanks of the insect, thus
diminishing the vibratory area and damping the sound.

The gentle touch of a finger-tip muffles the sharp, loud ringing of a
glass tumbler or "musical-glass" and changes it into a veiled,
indefinite sound which seems to come from a distance. The White Cricket
knows this secret of acoustics. It misleads those that seek it by
pressing the edge of its vibrating membranes to the soft flesh of its
abdomen. Our musical instruments have their dampers; that of the
_OEcanthus pel