§ 827. THE INSECTA. 4G7 
are caused by the rubbing of their prothorax against the peduncle of the 
mesothorax, or by grating the ridges of the abdomen against the internal 
surface of the elytra, Reduvius stridulus, Mutilla europaea, and Mantis 
religiosa, produce also certain sounds by the friction of particular portions 
of their skeleton. The males of many Acrididae produce their creaking 
sounds by playing, as with the bow of a violin, upon the lateral borders of 
their Elytra, by their posterior thighs which have a longitudinal granular 
ridge on their internal surface. The peculiar cry of the male Locustidae 
and Achetidae is produced by the base of their elytra. The very hard 
and sharp internal border of one of these elytra rubs against a horny ridge 
upon the under surface of the other, close to the tympanitic disc. 
With the males of the musical Cicadidae, there is a very remarkable sonif- 
erous apparatus, situated on the under surface of the first abdominal 
segment. It consists of two spacious drums at the base of which is a dry, 
plicated membrane, to which is attached a large muscle of conical form, 
arising from a median, bifurcated process of the second abdominal segment. 
The entrance of each of these drums is more or less covered by a round- 
ing operculum which is free behind. The muscle draws the membrane 
inwards, then relaxing, this last returns by its own elasticity, producing, as 
from the bending up and down of a metallic plate, a loud, clanging sound. 
This sound is undoubtedly considerably increased by the resonance of the 
air in the drums and-in the neighboring vesicular tracheae. 
to be explained in various ways, but none of the 
oases yet assigned are satisfactory ; see Passerini, 
Ann, d. Sc. Nat. XIII. 1828, p. 332; R. Wagner, 
in Miller’s Arch. 1836, p. 60; Goureau, Nord- 
mann, and Duponchel, Ann. de la Soc. entom. VI. 
IX., or Wiegmann’s Archiy. 1839-41.* 
4 Bee Burmeister, Handb. &c. I. p. 507, and 
a in Silberman’s Revue Entom. III. p. 
5 See my observations in Wiegmann’s Arch. 
1844, I. p. 53. This fiddling movement may be 
easily observed with the males of Gomphoceros 
and Oedipoda. Pneumora maculata has, upon 
the sides of the second abdominal segment, a very 
strongly denticulate, oblique ridge, against which 
6 For this soniferous apparatus, see Goureau 
and Solier, Ann. d. la Soc. Entom. 1837, p. 31; 
Newport, Cyclopaed. loc. cit. II. p. 928, fig. 394- 
396; Goldfuss, Symb. ad. Orthopt. quorund. 
oeconomiam, Bonn. Diss. 1843, p. 6, fig. 1-10 ; and 
my observations in Wiegmann’s Arch. loo. cit. p. 
69. Burmeister (Handb. &c. I. p. 511) has 
sought to explain this sound by referring it to the 
powerful escape of the air from the stigmata of the 
Locustidae and Acrididae ; but this is unsatisfac- 
tory. 
7 For the soniferous apparatus of the musical 
Cicadidae, see Réaumur, Mém. V. 4th mém. Pl. 
XVII.; Burmeister, Handb. &c. I. p. 613 5 
Ratzeburg, Mediz. Zool. II. p. 208, Taf. XX VII. 
is rubbed, probably, a horny process ted on 
the internal surface of the posterior thighs. I am 
yet unable to account for the way in which the 
males of Oedipoda stridula produce their hoarse 
buzzing, during flight. 
* [ § 327, note 3.] Haldeman (Silliman’s Jour. 
May, 1848) states that Lithosia tata, Kirby, 
and especially Carus, Analekt. zur Naturwiss. p. 
142, fig. 1-18. 
European Acherontia atropos may produce its 
liar sound in a similar manner. — Ep. 
or an allied species, produces an audible stridula- 
tion by vibrating the pleura beneath the wings, 
this part being marked in recent specimens by par- 
allel lines, apparently indicating the position of the 
muscles. According to him, it is possible that the 
t [§ 327, note 7.] See also my investigations 
upon this apparatus of the Cicada septendecim in 
the Proceed. Boston Soc. Nat. Hist. 1851, p. 72.— 
Ep. 
