august, 1860. 155 



the order of Lepidoptera. The impression I have derived 

 from the study of it, induces me to believe that it is owing 

 chiefly to the artificial system by which it is at present inter- 

 preted, and which I have endeavoured to follow in this paper. 

 Numerous families, or so-called families, have been arbitrarily 

 instituted on the most trivial and untenable characters, some 

 of which are only sexual peculiarities, while ornamentation 

 appears to be a far more important element than structure, 

 in the diagnoses by which they are characterized. Such an 

 arrangement possesses a certain amount of convenience, inas- 

 much as it frequently enables the student or inquirer to limit 

 the probable number of genera to which an insect he may 

 wish to classify may belong. This, however, is its total sig- 

 nificance, and even in this respect it is often deficient and 

 deceptive. It* is a system of convenience and not of nature, 

 which works on categories of structure and recognizable con- 

 ceptions or ideas. 



In my own view, from which, doubtless, many naturalists 

 will dissent, ornamentation is purely an individual character- 

 istic of species, and, although in general sufficiently constant, 

 subject to a degree of variation in the same species that is often 

 very considerable. Why should that which is unstable in 

 species receive the stamp of scientific approval in the recog- 

 nition of superior groups, instead of that which is constant 

 and fixed, which is more or less indicative of modes of life, 

 which is the expression in the imago of those categories of 

 thought that we designate genera and families? I cannot 

 perceive why it should be preferred, when I recall the won- 

 derful fertility in structural invention which characterizes 

 every natural family, and the logical connections that exist 

 between all those groups of species composing its various 

 genera. If the specific conception is the same in the prepa- 

 ratory states, and the structure of the various imagos that 

 result is nearly identical, differing in some trivial peculiarity, 



* For " This is," which appears in the original, Dr. Clemens has marked in 

 pencil on the copy he sent me " It is." H. T. S. 



