SOUNDING ORGANS. Iv 



* Grundziige der Delphacini ' may be consulted for the 

 many small etchings relating to these parts ; also 

 Mr. Scott's numerous papers in the Ent. Mo. Mag., 

 vols. vii. and viii. 



On the Sounding Organs of the Cicada. 



Reaumur was the tirst author who studied the 

 anatomy of this insect with any pretence to accuracy. 

 His observations have been in great part confirmed by 

 those who have come after him. 



In Italy, which may be called the home of the 

 European Cicada, Filippo de Filippi early pointed out 

 that on the under side, below the thoracic scales, two 

 cavities are separated by an intermediate corneous 

 septum, and that from these cavities the well-known 

 stridor is produced, inappropriately called the song of 

 the Cicala or Cicada. Afterwards this author pointed 

 out the tw^o membranes which are concerned in the 

 production of the sound. 



More recently Prof. Targioni Tozzetti, of Florence, 

 took up this subject, and, still later, Dr. Cesar Lepori, 

 who published some interesting experiments, which 

 seem to put at rest the question how far the stomata 

 have anything to do with the stridulation. After 

 pointing out that Landois had no right to challenge 

 iieaumur's work, " because he never possessed a living 

 insect," since he himself laboured under the very same 

 disadvantage. Prof. Lepori describes the parts concerned, 

 and divides them into essential and accessory organs. 

 He first proceeded to remove, from a living specimen, 

 portions of the semilunar metathoracic scales, little by 

 little, and finally he took the whole of them from above 

 the cavities. Still he found that the Cicala chirped 

 equally well without, as with, these scales, and thus 

 he came to the conclusion that they acted merely as 

 protective coverings to the membranes below them. 



Two membranes appear in view, after the removal 



