REVISION OF SPECIES OF THE GENUS AGHOTIS, 7 



I have made use of the genital structure of the male for generic di- 

 visiou in one case only, where a very large series of si)ecies agree most 

 remarkably in structure, and the character becoming generically val- 

 uable, lost value in the recognition of species. 



The study of the primary sexual characters is one of the most val- 

 uable guides in the recognition of species. The structnres are within 

 my experience absolutely invariable within specific limits, and siiecies 

 otherwise closely allied are sometimes well separatetl by these charac- 

 ters. 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 dis- 

 tinctness of species when superficial characters left it in doubt. It has 

 removed individual judgment as a factor in many cases and allows a 

 final appeal in cases of difference. There is no universal test charac- 

 ter, however, and as with all others so sexual characters sometimes 

 fail. Over one hundred species referred to Carneades have so nearly 

 the same form of structure that there is no sufficient variation to have 

 specific value in doubtful cases. In some other groups, however, no 

 two species are alike, and the widest variance within generic limits 

 allows definite specific limitation. 



The work on the Agrotes was done in 1884 and 1885. At that time I 

 was employed by Professor Riley as n special agent of the Division of 

 Entomology, and the work was done in the intervals of the economic 

 work assigned to me. Professor Kiley sent me as a basis for the work 

 his entire collection, now in the National Museum. My own collection 

 was very fair in the genus, and is now also in the National Museum. 

 The Meske collection, containing many rare species aiul t;\pes, is now 

 also in the Museum collection. Mr. Tepper's collection contained a 

 very great part of Mr. Morrison's types, and these, as well as whatever 

 else I needed for study, were freely placed at my disposal. This col- 

 lection is now in the Michigan Agricultural College. Mr. Graef's col- 

 lection contains many of Mr. Grote's and some of ^Ir. Morrison's types, 

 and these also I had for study. Mr. Hulst as kindly allowed me the 

 use of his material, also containing some of Mr. Grote's types. The 

 grand collection of Mr. Henry Edwards was loaned me for study by its 

 owner, and contained many varieties, typical or authentic, which are 

 not or were not then elsewhere represented. Mr. Neumoegeu's collec- 

 tion had been at that time thoroughly revised by Mr, Grote and con- 

 tained a very large number of the types of Mr. Grote's later descrip- 

 tions, and to this also I had free access, and ^Ir. Neumoegen kindly 

 loaned me for study whatever T needed. At Philadelphia the collec- 

 tion of the American Entomological Society was opened to me, and at 

 Cambridge the courtesy of Dr. Hagen enabled me to study the material 

 there. At Salem I studied the material in the Peabody Academy of 

 Science, containing Dr. Paekaid's types. At Kittery Point I spent a 

 very enjoyable day with Dr. Thaxter, and there I had an opportunity 



