152 .CICADA. 



has justly claimed the attention of the most cele- 

 brated investigators. Reaumur and Roesel in par- 

 ticular have endeavoured to ascertain the nature 

 of the mechanism by which the noise is produced, 

 and have found that it proceeds from a pair of 

 concave membranes, seated on each side the first 

 joints of the abdomen : the large concavities of the 

 abdomen, immediately under the two broad la- 

 mellag in the male insect, are also faced by a thin, 

 pellucid, iridescent membrane, serving to increase 

 and reverberate the sound, and a strong muscular 

 apparatus is exerted for the purpose of moving 

 the necessary organs. 



The Cicada plebeja is thus distinguished by 

 Linnaeus as a species*, viz. Cicada with the tip 

 of the scutellum bidentated, and the upper wings 

 marked with four anastomoses and six ferruginous 

 lines. 



In this division of the genus Cicada are several 

 large and elegant insects, as the Cicada hcematodes, 

 distinguished by its body of a polished black 

 colour, with the divisions of the abdomen marked 

 by so many scarlet rings or bands, and the Cicada 

 atrata, which is of a fine black, varied beneath 

 with yellow streaks in .the direction of the abdo- 

 minal and thoracic divisions: the wings are black 

 to some distance from the base. In this tribe 

 also ranks the Cicada viridis, a large species, na- 



* It is to be observed however that from a great general 

 similarity between the Cicadae of this division or tribe, it is diffi- 

 cult to form specific characters sufficiently distinctive 3 and it 

 may be doubted whether the present be so. 



