HEMIPTERA. 



103 



shape of a sheath, or case, enveloping the body when the insect is at 



rest ; these are transparent and destitute of colour, or sometimes 

 ■ adorned with bright and varied hues. The legs are not in the least 



suited for jumping. The female is provided with an auger, with 



which she makes holes in the bark of trees in which to lay her eggs. 



The male (Fig. 78) is provided with an organ, not of song, but of 



stridulation or screeching, which is very rudimen- 

 tary in the female. We will stop a moment to 



consider the apparatus for producing the song, or 

 . rather the noise, of the male Cicada, and the 



structure of the female's auger. We are indebted 



to Re'aumur for the discovery of the mechanism 



by the aid of which the Cicada produces the sharp 

 ' noise which announces its whereabouts from afar. 



We will give a summary of the celebrated Memoir 



in which the French naturalist has so admirably 

 '. described the musical apparatus of the Cicada.* 

 It is not in the throat that the Cicada's organ 



of sound is placed, but on the abdomen. On 

 ; examining the abdomen of the male of a large 

 j species of Cicada, one remarks on it two horny 

 jj plates, of pretty good size, which are not found 

 *ion the females. Each plate has one side straight ; 

 (the rest of its outline is rounded. It is by the Fig. 78. -Cicada (Male), 

 iside which is rectilinear that the plate is fixed 

 li immediately underneath the third pair of legs. It can be slightly 

 [(raised, with an effort, by two spine-like processes, each of which 

 ij presses upon one of the plates, and when it is raised, prevents it from 

 !| being raised too much, and causes it to fall back again immediately. 

 I If the two plates are removed and turned over on the thorax, and 



[the parts which they hide laid bare, one is struck by the appearance 

 which is presented. " One cannot doubt that all one sees has been 

 made to enable the Cicada to sing," says Reaumur. " When one 

 compares the parts which have been arranged so that it may be able 

 to sing, as we may say, from its belly, with the organs of our throat, 

 one finds that ours have not been made with more care than those 



jiby means of which the Cicada gives forth sounds which are not 



}j always agreeable." 



' We here perceive a cavity in the anterior portion of the abdomen 



jand which is divided into two principal cells by a horny triangle. 



* "Memoires," tome V. 4to. 



