CHAPTER III 



THE CLASSIFICATION OF MOTHS 



"The filmy shapes that haunt the dusk." 



TENNYSON, In Memoriam, xciii. 



THE insects of to-day, like the animals of all other classes 

 found upon the globe, represent lines of descent from an ancestry, 

 which runs back into the remote geologic past. The attempt to 

 trace the lines of descent in any order by studying the resem- 

 blance between genera and species as they exist to-day, while 

 throwing considerable light upon the subject, can never yield 

 wholly satisfactory results in the absence of testimony derived 

 from the field of paleontological inquiry. The study of fossil insect 

 life is as necessary to elucidate the story of the development of 

 the insect world, as the study of fossil vertebrates is necessary in 

 order to understand the manner in which existing mammals have 

 been derived from preexisting forms. At best descent can only 

 be positively asserted within the lines of those groups, to which 

 naturalists have given the name of families. Within these it is 

 possible to declare of this or that genus that it has been possibly, 

 or even probably, derived from the same stock as another. 

 Reference to a common ancestral form may safely be predicated 

 of very few families, so far as such assertion of a common 

 parentage rests upon evidences found in the living structures of 

 to-day. 



All attempts to classify the lepidoptera in such a manner 

 as to show the derivation of one of the existing families from 

 another, and to maintain a lineal sequence in the order given, 

 must necessarily prove wholly disappointing. The fact is, that 

 the various families represent divergences from the parent stem, 

 which may be likened to the divergence of the branches from the 

 trunk of a tree. Any system of classification, which leaves this 



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