108 EVENINGS AT THE MICROSCOPE 



The most elaborate contrivance for the production of 

 sounds among the Insect races, however, is found among 

 the Cicadae, celebrated in classical poetry as the very im- 

 personations of song and eloquence. I regret I cannot 

 show you this apparatus; for though we have a British 

 species lately discovered in the New Forest it is very 

 rare. Should you travel, however, either in the old or 

 new world, you will have abundant opportunities of using 

 your microscope to verify the following description by 

 our prince of entomologists, Mr. Kirby. 



"If you look at the under side of the body of a male, 

 the first thing that will strike you is a pair of large plates 

 of an irregular form in some semioval, in others tri- 

 angular, in others again a segment of a circle of greater 

 or less diameter covering part of the belly, and fixed to 

 the trunk between the abdomen and the hind legs. These 

 are the drum- covers or opercula, from beneath which the 

 sound issues. At the base of the posterior legs, just above 

 each operculum, there is a small pointed triangular proc- 

 ess, the object of which, as Reaumur supposes, is to pre- 

 vent them from being too much elevated. When an 

 operculum is removed, beneath it you will find on the 

 exterior side a hollow cavity, with a mouth somewhat 

 linear, which seems to open into the interior of the ab- 

 domen: next to this, on the inner side, is another large 

 cavity of an irregular shape, the bottom of which is di- 

 vided into three portions; of these the posterior is lined 

 obliquely with a beautiful membrane, which is very tense 

 in some species semiopaque, and in others transparent 

 and reflects all the colors of the rainbow. This mirror 

 is not the real organ of sound, but is supposed to modu- 

 late it. The middle portion is occupied by a plate of a 



