( xxvi ) 



self-evident that we ask onrsclvos in wonder liow it is possible that there 

 are systematists wlio do not— should we say will not? — recognise the necessity 

 of it. If Frlmjilla coelehs is accepted as a formula for a species, Sphinx 

 atlunticus is also a designation of a spei-ies, and not of a genus or a variety 

 or a subspecies. To speak of " species " Sphinx ocellata and of " subspecies " 

 Sphinx atlanticiis is a contradiction unworthy of science. 



In i'ornicr times varieties were looked upon as freaks of nature. They were 

 to many a classifier an interesting nuisance, which often threatened to upset 

 the balance of his well-fixed species, and were on that account more often 

 entirely put aside than welcomed as an object for research. Esper, who went 

 perJiajis deeper into the phenomena of variation than most of his contemporary 

 entomologists, already distinguished between ordinary varieties (Abweichungen) 

 and abnortnal individuals (Ausartungen). However, as long as the principle of 

 evcilution underlying these varieties was not recognised, there was no need to 

 study them systematically, and to work out a system of nomenclature which 

 would bring into order the chaos of varieties, as did Linne's binominal system 

 tlie chaotic mass of sj)ecies. 



From Linn(5 onwards varieties, if provided with a distinctive name, are 

 recorded in various ways. The following names may serve as illustrations : 

 Papilio iris luteus ; Columba oenas j3. domestica ; Phasianus gallus /3. gallus 

 cristatus ; Phasianus colchicus (/3.) Phasianus varius. The word varietas, 

 introduced by Linn6 as subordinate to species, meant anything deviating 

 obviously from the normal individuals of a species. The practice of putting the 

 term in an abbreviated form, as rarid. or m;-., before the varietal name does 

 not seem to have sprung up before the beginning of the nineteenth century, 

 and the use of the term aberratio {ab. = aberr.) is still younger. Not rarely 

 the "variety" was in reality the normal form, while the "species" happened 

 to be described from aberrant specimens. There was no strict rule for the 

 emjtloyment of var. or ab. ; some treated well-marked varieties as var. and less 

 obviously different individuals as ab., the distinction between var. and ab. being 

 merely quantitative ; while others employed ab. for abnormal specimens occurring 

 singly among the normal ones, and var. for the regularly observed varieties. 

 There are many collectors and classifiers, representing the stagnant element 

 in this department of our science, who look at varieties still from either of 

 these standpoints. 



Since the middle of the last century, when natural science stepped from 

 childhood into manhood, the study of variation has gradually become more 

 methodical, with a change in the 



PRINCIPLES OP CLASSIFICATION, 



and has now attained a height of which our forefathers in science did not dream. 



New lines of research bring to light new series of facts ; and new kinds 



of facts recpiire a new terminology. It will not do to have the same 



nomenclatorial formula for a sj)ecies as for a genus ; and so it will also not 



