242 THE ENTOMOiiOGlS'I'. 



which control zoological evolution ; for we find from time to 

 time aberrations cropping up, which would not seem to be 

 founded upon any ancestral tendencies, but to be sporadic, and 

 which only evidence the production of similar results from 

 similar causes. The very rare and strangely similar aberrations 

 of the undersides of certain of the Vanessidse are cases in point. 

 When, however, recurring inherited variations occur and are 

 either local or resulting from seasonal influences, or from what 

 is termed mimicry, &c., we feel it necessary to define their 

 characters more fully than by the inclusive term "variety" 

 formerly applied to all. In classification, however, it hitherto 

 has been thought sufficient to compile a list discriminating only 

 on the one hand between the adventitious or occasional appear- 

 ance of any variation meriting record, and on the other, those of 

 similar importance which are reproduced in inherited sequence. 

 These classes of forms are almost universally termed "aberra- 

 tions" and "varieties" respectively in such catalogues as Stau- 

 dinger's. A few authors, indeed, shut their eyes to even this 

 fundamental distinction, which indicates a difference between 

 the fleeting and the stereotyped variation, and apply the term 

 "variety " to every deviation from the specific type. It is true that 

 the border line between the stable and the unstable form is not 

 absolutely definable; but if such an objection be insisted on, we 

 should have to acknowledge what we must be convinced of 

 theoretically, that the definition of species is beset with similar 

 defects. But this school is not likely to satisfy the requirements 

 of the present day, for the tendency, as pointed out by Mr. 

 Mansbridge, is rather to adopt a more complex terminology, 

 capable of more precisely indicating the idiosyncrasy, so to 

 speak, of the variety in question. And though in classified lists 

 a multiplication of such terms might be redundant and un- 

 necessary, yet in zoological literature their use is almost impera- 

 tive as our knowledge accumulates. The question therefore 

 becomes narrowed into the consideration of what classes of 

 varieties require special designations suggestive of some salient 

 feature of their phylogeny, or distribution, or morphological 

 attributes. And here I would point out that some synonymous 

 general terms are very valuable. The words "variation" and 

 "form" are of the utmost value to a writer when he wishes to 

 avoid tautology, or speak indefinitely. The " forms " or " varia- 

 tions " of any species may thus be spoken of generally ; and then 

 defined particularly as " aberrations " or " varieties " as the case 

 may be. It would be a pity to abolish our indefinite terms ; for 

 if we do, literary necessities will oblige other substitutes to be 

 employed. The terms "form" and "variation" therefore might 

 advantageously remain without any restrictive application, as 

 has generally been the usage hitherto. Now as to the divisions 

 into which it might be desirable to arrange varieties. One of 



