SCIENTIFIC NOTES. 151 



since I have demonstrated the near relation between the two faunae 

 exhibited by Noctuid/E of the old and new world. The characters 

 drawn from the male genitalia must be ranked with those from the 

 antennae. 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^ are found to differ markedly in other- 

 wise very closely related species. In other species, easily distinguish- 

 able, 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 impracticable to classify 

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

 by Herrich-Schaffer. 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, 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 so far the American examples may be picked out by experts. 

 When these conditions can no longer be fulfilled there would be no 

 ground for retaining a different name. The mere fact of their inhabit- 

 ing differing continents is not sufficient, they must breed true to type 

 and not produce each other. Then we can be sure we have to do 

 with separate cycles of existence, and we can catalogue the fact. As 

 the genitalia are concealed, their structure is not so apparent, and it is 

 clear that repeated observations are necessary to verify the statements 

 drawn from solitary dissections. But, granting what has been published 

 as substantially reliable, there yet remains the test of breeding 

 to be applied to the genitalic species. We have an instance in 

 the genitalic species ot Nisionades. These butterflies have not been 

 bred to ascertain if they remain true in their genitalic peculi- 

 arities, if one genitalic type does not produce the other, if the 

 caterpillars show no differences. Until all the matters are cleared up 

 we can arrive at no final conclusion as to the value of genitalic cha- 

 racters, as to which single observations must be checked by repeated 

 experiments. Writers on the subject have apparently proceeded on the 

 basis that the male genitalia are formed, not by deposits of chitine but 

 of cast iron, moulded so as to fit and give at last a stable and firm 

 reality to our artificial system of classification. Vain expectations. 

 The characters on which we are obliged to found all our categories, 

 are one in quality and only differ in quantity ; what is generic is 

 specific also, and what is specific is varietal." — Canadian Entomologist. 

 July, 189T. 



