CLASSIFICATION. XXXV 



In the 'Entomologist' (vol. xxii. p. 270) I sug- 

 gested a sketch-plan for the British Cicada) which is 

 almost identical with the foregoing Synopsis. It 

 met with some criticism in the following number of 

 that magazine, the substance of which was that, as 

 almost all the British insects are songless, they 

 ouglit to be referred to different families ; in short, 

 that these insects, hitherto grouped with Cicadae, are 

 not Cicads at all. 



It has been said that " if you take care of the 

 species, the genera can take care of themselves." 

 Species, for all practical purposes, are natural facts. 

 Families, sub-families, tribes, and sections are de- 

 ductions from facts ; and these are different things. 

 Necessarily, different values will be given to one or 

 the other term, and hence we see the existence of 

 several classifying systems. If we could have an 

 authoritative consensus of opinion as to what shall, 

 in future, constitute a section or a family ; biological 

 systems could be constructed on well-defined lines and 

 recognized principles. 



Fabricius's words, applied to genera, " optima 

 nomina quas nil significant," are scarcely applicable 

 to wide classifications, since terms must have defi- 

 nite meanings to fulfil their purposes. Burmeister 

 says, " System has the advantage of not regarding 

 solitary characters only, but all collectively ; and can 

 therefore only separate and connect where nature 

 has marked a separation and connection." Some 

 may be able to give their reasons why Cirius has 

 no claim to be considered one of the Cicadinae ; 

 others may have equally strong reasons to advance 

 the other way ; and thus the weakness of a purely 

 artificial system may be brought out. 



Without questioning the point that the true 

 Cicadinae form a natural group, it is contended that 

 the morphological and other differences hetween A pliis, 

 Schizoneura and Phjlloxcra are greater than between 

 Cicada, Cixius, and Aphrophora ; yet the former groups 



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