A CODE OF VARIETAL NOMENCLATURE. 151 



ordinary rules for specific names have been held equally 

 admissible for varietal ones. Thus we have Tripliana orbona 

 ciirtisii, named after an individual ; Tliera juniperata scotica, 

 after the country it inhabits ; Mamestra persicariae unicolor, 

 having reference to the colour ; and so on. 



Considering this, and considering the nature and relations of 

 varieties, it seems to me that while we are yet comparatively 

 early in the history of the science, and the vast majority of 

 varietal forms remain as yet unclassified, it is extremely 

 necessary to make all possible arrangements for the simplifi- 

 cation of the nomenclature. Of course to those who are studying 

 a group in detail, and know well every varietal form within its 

 limits, it will matter little what names they use, since one name 

 is as good as another (if grammatical, and easy to pronounce and 

 write), after once it has been fixed in the mind and associated 

 with a certain known object. But when it is remembered how 

 many species there are, and how each one will probably have at 

 least one variety differing from the type, and variable species 

 very many, it is quite clear that any but the strictest specialists 

 will experience considerable difficulty in remembering the 

 characters of named varieties, which difficulty would be greatly 

 lessened if the names themselves were so contrived as to 

 indicate the nature of the variation. This is, indeed, done in 

 many cases ; but what I wish now to propose is this : — That in 

 all cases in which the same kind of variation is common to two or 

 more species, some name shall be adopted which shall be used to 

 distinguish the variety in whatever species it may occur, and 

 shall, as far as possible, express the character of the variation ; 

 except when some other name has been proposed, in which case 

 the rules of priority could not well be infringed.* 



Example. — The red pigment of several species of moths, such 

 as ZycjcBna, has a tendency to become altered to yellow, either by 

 some change in the arrangement of its molecules, or by its 

 splitting into a simpler compound. This change, whenever it 

 occurs, may be expressed by the name " lutescensJ" For 

 examples : — 



Zygcena filivenduUe liitescens. Entom., 1879, 225; Ent. Mo. 

 Mag., 1877, 67. 



* Unless some inttrnational cf nimittee -ncre appointed, by the common consent 

 of entomologists, to deal ■with such matters; and I hope that some day this may 

 be done. 



