movement of the neck within the pro-thoracic cavity. According to
Westring, Reduvius personatus also stridulates. But I have no reason to
suppose that this is a sexual character, excepting that with non-social
insects there seems to be no use for sound-producing organs, unless it
be as a sexual call.
ORDER: HOMOPTERA.
Every one who has wandered in a tropical forest must have been
astonished at the din made by the male Cicadae. The females are mute;
as the Grecian poet Xenarchus says, Happy the Cicadas live, since they
all have voiceless wives. The noise thus made could be plainly heard
on board the Beagle, when anchored at a quarter of a mile from the
shore of Brazil; and Captain Hancock says it can be heard at the
distance of a mile. The Greeks formerly kept, and the Chinese now keep
these insects in cages for the sake of their song, so that it must be
pleasing to the ears of some men. (23. These particulars are taken from
Westwood s Modern Classification of Insects, vol. ii. 1840, p. 422.
See, also, on the Fulgoridae, Kirby and Spence, Introduct. vol. ii.
p. 401.) The Cicadidae usually sing during the day, whilst the
Fulgoridae appear to be night-songsters. The sound, according to
Landois (24. Zeitschrift fur wissenschaft. Zoolog. B. xvii. 1867, ss.
152-158.), is produced by the vibration of the lips of the spiracles,
which are set into motion by a current of air emitted from the
tracheae; but this view has lately been disputed. Dr. Powell appears to
have proved (25. Transactions of the New Zealand Institute, vol. v.
1873, p. 286.) that it is produced by the vibration of a membrane, set
into action by a special muscle. In the living insect, whilst
stridulating, this membrane can be seen to vibrate; and in the dead
insect the proper sound is heard, if the muscle, when a little dried
and hardened, is pulled with the point of a pin. In the female the
whole complex musical apparatus is present, but is much less developed
than in the male, and is never used for producing sound.
With respect to the object of the music, Dr. Hartman, in speaking of
the Cicada septemdecim of the United States, says (26. I am indebted to
Mr. Walsh for having sent me this extract from A Journal of the Doings
of Cicada septemdecim, by Dr. Hartman.), the drums are now (June 6th
and 7th, 1851) heard in all directions. This I believe to be the
marital summons from the males. Standing in thick chestnut sprouts
312