(_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. _Early Stages._--The food-plant is clover. The eggs are pale yellow, changing, after being laid, to crimson. The caterpillar is slender, green, striped longitudinally with paler green. The chrysalis is pale green. The species ranges from New England to Florida, and westward to the Rocky Mountains. (5) =Colias chrysomelas=, Henry Edwards, Plate XXXV, Fig. 12, ♂; Fig. 13, ♀ (The Gold-and-black Sulphur). _Butterfly._--Larger than _C. philodice_. The male on the upper side is bright lemon-yellow, with broad black margins on both wings. The female is paler, with the black margin of the hind wing lacking or very faintly indicated, and the margin of the fore wing much broken up by yellow spots. On the under side the wings of the male are dusky-orange, pale yellow on the disk of the primaries; the wings of the female on this side are pale yellow. Expanse, ♂, 2.00-2.10 inches; ♀, 2.25-2.30 inches. _Early Stages._--Undescribed. The home of this species is on the Coast Range of northern California. (6) =Colias alexandra=, Edwards, Plate XXXV, Fig. 6, ♂; Fig. 7, ♀ (The Alexandra Sulphur).