THE CANADIAN ENTOMOLOGIST. 135 



just what I think, too, and I have made two journeys in the west, and a 

 great many in Europe and Asia in search of this knowledge ; whilst Mr. 

 Edwards, so far as I know, has never seen an (Eneis alive anywhere or 

 any collection of them at all comparable with those I have seen and have 

 studied specially before wiiting. 



As to his criticism on the value of the clasper I do not think he has 

 any practical experience of the matter, but I will leave Mr. J. Edwards 

 to answer him on that point : — 



"I desire to say something on so much of Mr.W. H. Edwards's critic- 

 ism above-mentioned, as relates to the employment of characters derived 

 from the male genitalia and the comparative table, as these are the points 

 with which I was more particularly concerned in the preparation of Mr. 

 Elwes's paper on (Eneis. 



" My business was simply to examine the material upon which the 

 paper was based, and to ascertain how many kinds there were capable of 

 definition with reasonable accuracy ; and I endeavoured to give expres- 

 sion to those characters which separate any given kind from all the other 

 kinds under review at that time, and to contrast these characters in a 

 workable form in my " Conspectus specierum." The question of the 

 soundness or otherwise of my work I am content to leave to the judgment 

 of any competent students who may be disposed to make an honest 

 attempt to determine described species of CEneis by the characters there 

 laid down. A comparative table may be very useful to many students 

 without necessarily pleasing everybody. Mr. W. H. Edwards gives it as 

 his opinion that characters drawn from the male genitalia are valueless, 

 but I find in practice that they have a value equivalent to any other mor- 

 phological peculiarity, and that value is, of course, in direct proportion to 

 their constancy in a series of individuals. Perhaps the best statement of 

 the exact value of these characters, so far as Lepidoptera are concerned, is 

 that by Prof John B. Smith in his Revision of Agrotis (Bull. 38, U. S. 

 Nat. Mus., p. 7.), which I quote here as it is well worth reprinting : — 

 ' The study of the primary sexual characters is one of the most valuable 

 guides in the recognition of species. The structures are within my ex- 

 perience absolutely invariable within specific limits, and species other- 

 wise closely allied are sometimes well separated by these characters. 

 They have proved invaluable in settling questions of the identity of 

 American and European forms so closely allied as to be considered races, 

 and in several instances they have proved the identity or distinctness of 



