THE CANADIAN ENTOMOLOGIST. 147 



THE MALE GENITALIA AND THE SUBDIVISIONS OF 



AGROTIS. 



BY A. R. GROTE, A. M., BREMEN, GERMANY. 



It is forty years ago since Lederer used the male genitalia to group 

 the European species of Agrotis. According to the latest general work 

 on the subject, the 127 European species oi Agrotis fall into nine groups, 

 characterized chiefly by changes in the form of the male genitalic 

 appendages. The failure to correlate these European groups with the 

 American subdivisions of Agrotis, prevents me from considering Prof. 

 Smith's recent revision as complete, since I have demonstrated the near 

 relation between the two faunse exhibited by Noduince of the Old and 

 New World. 



The characters drawn from the male genitalia must be ranked with 

 those from the antennas. They are sexual or secondary characters. On 

 this account to use them as the sole basis for generic separation is hardly 

 necessary. The genitalia in the Noctuid(z are found to differ markedly 

 in otherwise very closely related species. In other species, easily distin- 

 guishable, they are practically of the same pattern. Undoubtedly we 

 must know and study all the parts of an insect, but no single character 

 will enable us to classify an order. It will be found as impracticable to 

 classify the moths by their tails, as by their wings alone or chiefly, as 

 attempted by Herrich-Schseffer. Among the representative species this 

 change in the structure of the genitalic appendages is instructive and 

 indicative of their morphological value. The European Agrotis augur is 

 a well marked and tolerably isolated species, presenting peculiarities in 

 shape, size, colour and pattern. In all these respects the American 

 Agrotis haruspica is nearly its exact counterpart. As the basis of 

 separation of the two, the immature stages not having been used, we 

 have a tendency to obsolescence of certain markings and perhaps a hardly 

 perceptible change in the exact shade and average size in haruspica. 

 Now the genitalia are shown to differ in pattern as well. From this fact 

 we must logically conclude that the genitalia are more easily impressed 

 and changed by environment than colour, size and pattern, or other 

 structure. Consequently the genitalia are subject to variation, and the 

 question rather comes up, are the characters drawn from the male genitalia 

 of specific value? The true ground for considering the two species 

 distinct is that they do not interbreed and produce each other, and that 



