(5) Lycæna pseudargiolus (Boisduval & Leconte), [Plate XCI], Fig. 2, ♂; Fig. 3, ♀. Form neglecta Edwards, [Plate XCI], Fig. 4, ♂; Fig. 5, ♀. Form lucia Kirby, [Plate XCII], Fig. 1, ♂, under side. Form marginata Edwards, [Plate XCII], Fig. 2, ♂, under side; Fig. 3, ♂, upper side. Form nigra Edwards, [Plate XCII], Fig. 4, ♀ (The Common Blue).
This insect which is very common and may be found upon the wing from early spring until late in the autumn illustrates in a remarkable manner the phenomenon of polymorphism; that is to say, it has a number of forms, some of which are seasonal, some of which are sexual, some of which are climatic. It is in fact only through the labors of the late William Henry Edwards that some of the mysteries were cleared up, he having by breeding established the fact that some of the so-called species could be raised from eggs derived from one common stock. The great series of specimens upon which his conclusions were founded are in the possession of the writer, and have from time to time been supplemented by a vast amount of other material all of which confirms his teachings.
The forms lucia and marginata are winter forms, coming from chrysalids which have endured the long cold of the winter months and are the first to appear in spring. They are the only forms which occur in the far north near the Arctic Circle.
The forms pseudargiolus and neglecta are summer forms of the second and third generations, produced from eggs laid by lucia and marginata. Nigra is a dimorphic female form belonging to the summer broods and is melanic; that is to say, it is a form in which dark color prevails. Students of biology recognize a tendency in some animals to become black, while there is also a tendency to become white, or to produce albinoes. These tendencies in opposite directions in color are often observed in butterflies, and the melanic female of the species under consideration illustrates it. There is still another form, piasus, which occurs in Arizona and Mexico, and is climatic, or due to the influence of environment.
The winter forms are dwarfed and darkly marked on the under side as our figures show; the summer forms are larger, pale on the under side and dark on the outer borders above.
The species has a range in the expanse of wing of from 0.85-1.25 inch.
It occurs from Alaska to Florida, and from Anticosti to northern Mexico.
PL. XCIII
(6) Lycæna amyntula Boisduval, [Plate XCIII], Fig. 1, ♂; Fig. 2, ♀ (The Western Tailed Blue).