ENTOMOLOGY. 



each other, that produce by friction the sounds described. In each 

 surface this part presents a kind of ocellar spot with an uneven face, 

 in some parts elevated, in others depressed, and the elevations in 

 one accord exactly and bed into the depressions of the other when 

 they are not in action ; and very little exertion, it appears, when 

 they act against each other is sufficient to produce those astonishing 

 sounds for which this insect is so eminently distinguished. Those 

 characteristic organs of sound which the Rev. Mr. Guilding notices 

 so fully, are not indeed to be considered as peculiar to this species ; 

 it is the distinctive mark of a natural tribe of the Locusta tribe, and 

 which among modern systematists may be divided into several genera. 

 We have long since published an account of two very curious species 

 of this kind from the island of Ceylon, in our Natural History of 

 the insects of India," and we are well acquainted with others; but it 

 must be allowed that Mr. Lansdown Guilding has described those 

 organs and defined their use more fully than any of his predecessors. 

 All insects, it may be presumed, possess the power of emitting sounds 

 in a greater or less degree, and many are highly sonorous, but those 

 sounds are by no means uniformly produced by the same means ; 

 they differ in this respect materially, and it is such material deviations, 

 as in the present instance, that deserve particular attention. 



The figures in the succeeding plate (123) represent the organs 

 of sound, peculiar to the male insect, and which may be noticed in 

 this place : that delineated on the left side is fig. 5, and on the 

 opposite side is fig. 6, the description of which is thus given by 

 Mr. Guilding in his manuscript. 



" Crepitaculum (instrumentum soni) ocellus subdiaphanus ad 

 basin elytrorum. Fig. 4, 5, 6. maris. 



