The habitat of the species is on the lofty peaks of the Western Cordilleras.
(3) Colias eurytheme, Boisduval, Plate XLVIII, Fig. 18, ♁; Plate XXXIII, Fig. 5, ♂, under side; Plate II, Fig. 1, larva; Plate V, Fig. 53, chrysalis (Eurytheme).
Butterfly.—This species has been made in recent years the subject of exhaustive study, and has been discovered to be strongly polymorphic—that is to say, liable to great variation. Not only does albinism assert itself in the production of white forms, but there are many seasonal and climatic forms. We are not yet through with our studies, and there is doubtless much more to be ascertained. The figures cited above represent the typical form of the species. We have given, in addition to these, the following forms:
(a) Winter form ariadne, Edwards, Plate XXXVI, Fig. 7, ♂; Fig. 8, ♁. This form, emerging from chrysalids which have overwintered, is like the type in having the fore wings tinged with orange. Expanse, 1.75 inch.
(b) Winter form keewaydin, Edwards, Plate XXXVI, Fig. 9, ♂; Fig. 10, ♁. This is a larger form, more deeply flushed with orange, though not quite as deeply as shown in the plate. Expanse, 1.85 inch.
(c) Summer form eriphyle, Edwards, Plate XXXV, Fig. 15, ♂; Plate XLIII, Fig. 3, ♂, under side. This summer form differs from typical C. eurytheme in being yellow and not laved with orange. Expanse, 2.00 inches.
Early Stages.—The caterpillar feeds on clover, as do most of the species of the genus.
The range of eurytheme is very wide. It extends from the Atlantic to the Pacific, and from Canada to the far South, though rare in the lower parts of Florida and Texas in the hot lands.
(4) Colias philodice, Godart, Plate I (Frontispiece), Fig. 4, ♂; Fig. 5, ♁; Plate II, Fig. 10, larva; Plate V, Figs. 54, 55, chrysalis (The Common Sulphur).
Butterfly.—We are all familiar with this species, the "puddle butterfly" of our childhood, which sits in swarms on moist places by the wayside, and makes the clover-fields gay with the flash of yellow wings in summer. There are many aberrational forms, albinos and negroes, white forms and dark forms, dwarfed forms and large forms, but in the main the species is remarkably constant, and seasonal forms and distinctly local races do not abound as in the case of the preceding species. Expanse, ♂, 1.25-1.80 inch; ♁, 1.60-2.25 inches.