NEURATION OF THE WINGS. XXXlll 



the Mammalia, for certain pigs are known to have 

 forty-four, and others as many as fifty-four, vertebra3. 



As the stripes in no two leaves of the ribbon-grass 

 are strictly alike, so there need be no wonder that the 

 areolets and the wing-cells of Cicadas bounded by 

 branching nervures will sometimes show divergences 

 in individuals of the same species, and even that the 

 venation of one side should sometimes differ from 

 that of the other in the same insect. Not a few 

 examples of such may be found in my plates. Such 

 discrepancies, however, have not been chosen to illus- 

 trate this fact. 



From what has been said it may be gathered that, 

 although the neuration in the wings of insects is of 

 high value for classification, it must not be implicitly 

 or blindly followed ; and this remark is particularly 

 true as regards the numerous small Cicadas which do 

 not stridulate, amongst which we find it often happens 

 that normal nervures are absent in their elytra, having 

 been absorbed into the substance of the chitin ; and 

 that, in other instances, the presence of supernumerary 

 nervures in the same genus are indicated by the fur- 

 cation or splitting of veins into ramifications. 



The following Synopsis is added to show the position 

 taken amongst Haustellate insects by the Tcttigida), 

 under which tribal name I propose to combine the 

 Stridulantes, or Stridulantia of Burmeister, and the 

 Silentes, or Cicadelles of Latreille. 



N.B. — Derivatives should proceed from the genitive 

 case: thus Tettigidne from " tcttlgos," like Aphididse 

 from " aphidis." 



