(5) Argynnis aphrodite (Fabricius). [Plate XIII], ♀, under side (Aphrodite).
Closely resembling the preceding species, but smaller. The under side of the hind wings has the submarginal band narrower than in A. cybele and often wholly wanting, as shown in the figure. The fore wings on the under side are redder at the base than in A. cybele. Expanse 3 to 3.5 inches.
The range is the same as that of the preceding species.
The two species A. cybele and A. aphrodite usually are found flying at the same time and in the same places, and when on the wing it is often very difficult to distinguish them from each other. In fact they seem to intergrade into each other, and in a long series of specimens such close resemblances often occur that it is puzzling to decide which is which. The deeper red of the fore wing of A. cybele is the best diacritical character. The paler outer margin of the hind wing of A. aphrodite, which is typically shown in [Plate XII], sometimes occurs also in A. cybele, and I have specimens of the latter which very closely approximate the former in this regard. In selecting specimens for illustration I have chosen the two extreme forms in which the pale wing of A. aphrodite is seen to contrast on the under side with the darker wing of A. cybele shown on [Plate XIII].
It may be remarked in passing that the genus Argynnis is very difficult, and the writer has been in the habit of comparing it to the genus Salix, the willows, among flowers. Botanists know how the willows seem to run together, and how hard it is to discriminate the species. The same thing is true of this great genus of butterflies with which we are now dealing. It is particularly true of the species which occur in the region of the Rocky Mountains, of which the writer has probably the largest collection in existence, including all of the types of the late William H. Edwards. The test of breeding has not been fully applied as yet to all of these forms, and it is doubtful whether some of them are more than varieties or local races. There is here a field of inquiry which should tempt some young, ardent, and careful student. The day for more thorough work is at hand, and I hope some reader of these pages may be converted to the task. Entomological study should become more intensive, as well as extensive. The fathers of the science have paved the way and laid foundations; it remains for the rising generation to complete the work which the fathers have begun.
PL. XIV
(6) Argynnis atlantis Edwards. [Plate XIV], ♂ (The Mountain Silverspot).
Smaller than A. aphrodite, with narrower wings, darker at the base on both the upper and lower sides. The submarginal band below is pale yellow, narrow, distinct, and always present. Expanse 2.25 to 2.5 inches.
Ranges from Quebec to Alberta and southward, but is confined to the Appalachian mountain ranges in southern Pennsylvania and West Virginia.