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POPULAR SCIENCE REVIEW. 
The Cicadse, which are the subject of M. Carlet’s memoir, were 
principally Cicada plebeia and C. hcematodes , and were found 
in the environs of Grenoble. As many vivisections were made, 
his observations must be more searching than those of Reaumur, 
who only examined dry specimens or those preserved in alcohol. 
C. orni and C. maculata have also been dissected in the dry 
state. C. plebeia is, however, regarded by M. Carlet as the type 
of the genus and as the 66 classical Cigale.” 
For description, the body of the insect will be supposed to be 
placed vertically, the head being above and the belly directed 
forwards. 
M. Carlet, for the sake of clearness, divides his description 
into an anatomical and a physiological section. Under the 
former category are comprised : — 
1. The Framework (“ charpente ”) of the Vocal Apparatus. 
2. The Vibrating Membranes. 
3. The Muscles in relation with the above. 
4. The Sonorous Cavities. 
5. The ct Stigmata,” or orifices of communication of these 
cavities with the exterior. 
A. The Framework of the Vocal Apparatus. — This includes 
the last “ somite ” of the thorax {metathorax) and the five or 
six first segments of the abdomen. 
1 . The Metathorax. — On the lower border of this “ somite,” 
in front of and between the “ peritrema ” (a horny circle sur- 
rounding the opening of a stigma, s, figs. 1, 2, 3), may be seen a 
small chitinous * * * § point, of which more anon, termed the apo- 
physis of the folded membrane (“ membrane plissee ” ap, fig. 3.) 
The metathoracic segment is roofed in by a partition ( ento - 
thorax) made up of two wing-like branches, having between 
them a mesial slit. The most salient part, however, of this 
somite is the organ called “ volet ” f by Reaumur, and other- 
wise known by the name of operculum % ( v , figs. 1 and 3). 
This is nothing more than a prolongation of the epimeron,§ 
and is not movable, as Reaumur believed. It is greatly de- 
veloped in C. plebeia , and has the shape of a semicircular scale 
of which the rounded edge descends as far as the second ring of 
the abdomen. It is necessary to raise it on either side in order 
to bring the anterior part of the musical apparatus into view. 
In female Cicadse these structures are rudimentary, and do not 
* Chitine is a horny substance, insoluble in caustic potash, of which 
almost all the hard parts of insects consist. 
t French, “a shutter.” % Latin, “ a lid.” 
§ One of the twopaired lateral elements of the pectus or lower half of a 
thoracic “ somite.” 
