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 froiri 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 

 species of Cicada, one remarks on it two horny 

 plates, of pretty good size, which are not found 

 on the females. Each plate has one side straight ; 

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

 side which is rectilinear that the plate is fixed 

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

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

 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. 



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 

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

 always agreeable." 



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

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



"Memoires," tome V. 4to. 



