88 Transaction*. 



Art. VI. — A Revision of the Classification of New Zealand Caradrinina. 



By E. Meyrick, B.A., F.R.S. 



[Read before the Wellington Philosophical Society, 4th October, 1911. J 



I have here revised the genera of Caradrinina occurring in New Zealand, 

 taking into consideration the large amount of work done in the group 

 of late years, especially by Professor J. B. Smith and Sir George Hampson. 

 Both these authors have done admirable work in the careful investiga- 

 tion of structural characters, but in my judgment both have made too 

 many genera, and have thus been led in some cases to rely upon points 

 of distinction that are indefinite, slight, unimportant, unnatural, or 

 even illusive and imaginary ; and Sir George Hampson has unfortunately 

 adopted a principle of generic nomenclature which I believe is not now 

 held by any other leading lepidopterists, and is never likely to meet with 

 general acceptance. It will be well, therefore, to begin by making some 

 general remarks explanatory of my own principles and practice in these 

 two subjects. 



In the matter of generic nomenclature I hold as follows : — 



(1.) A generic name is void if published without description. Hampson 

 agrees, but there are writers who do not. The names of Hubner's 

 Tentamen are therefore void. 



(2.) Where an original genus included more than one species, and the 

 author has not in any way expressed which species was typical, later 

 writers can limit the meaning of the genus at pleasure by expressed 

 intention (accidental limitation by casual mention has no effect), such 

 limitations taking effect in order of priority. Hampson assumes the 

 first species of those mentioned by the original author to be the type, 

 which is certainly simple, but has no other justification whatever, and 

 it would be equally simple to assume the last. 



(3.) Fifty years' use in a particular sense establishes a. title, and bars 

 claim of priority. 



On these principles a reasonable and legitimate use is obtained with- 

 out much disturbance of recognized nomenclature. 



As to the characterization of genera, no doubt the subject is a very 

 difficult one, and there will always be room for much difference of opinion. 

 But a genus must represent a definite section of a branch of the gene- 

 alogical tree ; it must not be made up of two sections tied together, or it 

 will be unnatural, and, whilst it is certainly not always possible to define 

 absolutely the distinction between two genera, an author must have struc- 

 tural grounds for referring any species to one or other, or the genera will 

 be impracticable. A genus must be geographically consistent : it must 

 have originated in one place only, and have spread thence to other regions, 

 and its geographical distribution should not be incongruous ; if it is, the 

 supposed genus should be regarded with suspicion. Closely allied species 

 must not be placed in genera regarded as phylogenetically remote. The 

 value of a character for generic definition can only be determined prac- 

 tically ; in one set of insects a particular character may be fixed and suffi- 

 cient for generic and even family limitation, and in another the very same 



