THE CANADIAN ENTOMOLOGIST. 105 



Ursula gets within a very few miles of Hunter, and that to reach Stony 

 Clove it would not be necessary for it to come from the Hudson Valley. 

 There are no natural obstacles to prevent a direct flight over the 

 Schoharie to Hunter. Through Stony Clove I have been only once, and 

 that by rail on my last visit to the mountains, when I did no collecting. 



As to the standing oi proserphia I have no opinion to offer. 



Mr. Edwards, on p. 55 in the note, makes some remarks on the 

 value of genitalia in determining species. On this point I have very 

 decided opinions. By his suggestion that " some seem to have 

 shrunk in the drying, others perhaps are done from the green subjects, 

 and are full and plump," Mr. Edwards shows that he has never looked 

 into the matter himself at all, else he would know that the structures are 

 chitinous and cannot shrink any more than the antennae, palpi or legs. 

 The preparation from the recent specimen, and that from one fifty years 

 old, would be alike in the same species. Do the parts vary ? Decidedly 

 no, or to so slight an extent as to be scarcely appreciable. I have ex- 

 amined dozens of specimens of some of our common noctuids, and found 

 no variation, however much the raaculation differed. In my study of the 

 Lachnosterfia many hundreds were examined, some specimens a dozen 

 years old, others just killed, and the correspondence was absolute. Do 

 they help us distinguish species ? Also, decidedly yes. But this needs 

 qualification. Identity of sexual structure does not necessarily mean 

 identity of species ; but on the other hand, difference in sexual structure 

 always means difference of species. I have found these structures of the 

 utmost value in the noctuidce, and in some genera that I have studied 

 would not hesitate to determine species from the genitalia alone. In 

 Lachnosterna I would agree to name any species of either sex from the 

 genital structures where it is one of the species I have figured. 



But Mr. Edwards is right in one respect. Sometimes the character 

 fails, and in an entire genus all the species will be practically alike. My 

 revision of Agrotis illustrates that most strikingly. In this, however, the 

 character shares with many another the burden of want of universal 

 application, and we must use it as far as it goes. In the noctuids it is 

 most valuable in separating closely allied species, and it often determines 

 for me the rank of a form when the other characters leave me in doubt. 

 I believe that all who have carefully studied these characters arc con- 

 vinced of their importance and high value in specific separation. 



