Genus COLIAS, Fabricius

(The Sulphurs)

"Above the arching jimson-weeds flare twos And twos of sallow-yellow b.u.t.terflies, Like blooms of lorn primroses blowing loose When autumn winds arise."

JAMES WHITCOMB RILEY

_b.u.t.terfly._--Medium-sized b.u.t.terflies, yellow or orange in color, with black borders upon the wings. In many species this border is heavier in the female than in the male.

[Ill.u.s.tration FIG. 147.--Neuration of the genus _Colias_.]

_Egg._--The egg is spindle-shaped, thickest at the middle, tapering at the apex and at the base, generally attached by an enlarged disk-like expansion to the point on which it is laid. The upper extremity is rounded; the sides are marked by small vertical ridges, between which are delicate cross-lines.

_Caterpillar._--The caterpillars strongly resemble in appearance those of the preceding genus, from which, superficially, they cannot be distinguished by any anatomical peculiarities. They feed upon _Leguminosae_, and especially upon clover (_Trifolium_).

_Chrysalis._--The chrysalids do not generally differ in appearance from the chrysalids of the genus _Meganostoma_, though the wing-cases do not form as high a keel-shaped projection from the ventral side as in that genus.

This genus is very extensive, being represented throughout the temperate regions of both hemispheres, and also occurring in the cooler portions of South America, especially along the ranges of the Andes. One species is found in temperate South Africa. The brightly colored b.u.t.terflies, which are sometimes found congregating in immense numbers in moist places, are familiar objects, and swarm upon the clover-fields and by the roadside in the summer months throughout the United States.

(1) =Colias meadi=, Edwards, Plate x.x.xVI, Fig. 5, ?; Fig. 6, ? (Mead's Sulphur).

_b.u.t.terfly._--The wings on the upper side are orange, greenish on the under side. The discal spot on the lower side is centered with green.

Expanse, 1.75 inch.

_Early Stages._--The life-history has been written by Edwards, and may be found in the pages of the "Canadian Entomologist," vol. xxi, p. 41.

The larva feeds on clover.

The species is alpine in its habits, and is found in Colorado from nine to twelve thousand feet above sea-level.

(2) =Colias elis=, Strecker, Plate x.x.xVI, Fig. 13, ?; Fig. 14, ?

(Strecker's Sulphur).

_b.u.t.terfly._--This species is discriminated from the preceding princ.i.p.ally by the narrower black margins on the wings of the male and the more abundant yellow maculation of the borders in the female.

Expanse, 1.55-1.90 inch.

_Early Stages._--Closely resembling those of the preceding species, of which it may be only a varietal form.

The habitat of the species is on the lofty peaks of the Western Cordilleras.

(3) =Colias eurytheme=, Boisduval, Plate XLVIII, Fig. 18, ?; Plate x.x.xIII, Fig. 5, ?, _under side_; Plate II, Fig. 1, _larva_; Plate V, Fig. 53, _chrysalis_ (Eurytheme).

_b.u.t.terfly._--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 a.s.sert 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 x.x.xVI, 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 x.x.xVI, 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 x.x.xV, 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=, G.o.dart, Plate I (Frontispiece), Fig. 4, ?; Fig.

5, ?; Plate II, Fig. 10, _larva_; Plate V, Figs. 54, 55, _chrysalis_ (The Common Sulphur).

_b.u.t.terfly._--We are all familiar with this species, the "puddle b.u.t.terfly" 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 x.x.xV, Fig. 12, ?; Fig. 13, ? (The Gold-and-black Sulphur).

_b.u.t.terfly._--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 x.x.xV, Fig. 6, ?; Fig. 7, ? (The Alexandra Sulphur).

_b.u.t.terfly._--Larger than _C. philodice_. The male is pale canary-yellow, with much narrower black borders than the preceding species. The female is pale yellow or white, without black borders, or, at most, faint traces of them at the apex of the primaries. On the under side the wings are silvery-gray, yellow only at the base and on the inner margin of the primaries. The discal spot on the hind wings is white. Expanse, ?, 1.85 inch; ?, 2.10-2.30 inches.

_Early Stages._--The caterpillar is uniformly yellowish-green, with a white band on each side, broken with orange-red dashes running through it. The chrysalis, which resembles that of _C. philodice_ in form, is yellowish-green, darkest on the dorsal side, and adorned with three small red dots on the ventral side of the abdomen near the wing-cases.

The caterpillar eats _Astragalus_, _Thermopsis_, and white clover.

Expanse, ?, 1.90-2.15 inches; ?, 2.00-2.30 inches.

The species is found in Colorado and the mountain regions to the north and west of that State.

(7) =Colias interior=, Scudder, Plate x.x.xV, Fig. 10, ?; Fig. 11, ? (The Pink-edged Sulphur).

_b.u.t.terfly._--The male on the upper side closely resembles _C.

philodice_, but is smaller, the fringes of the wings rose-colored. The female is pale yellow above, more frequently white, with the tips of the fore wings lightly marked with blackish. On the under side the fore wings at the apex and the entire surface of the hind wings are rusty orange-yellow. The discal spot on the hind wings is silvery, bordered with rosy-red. Expanse, ?, 1.30-1.75 inch; ?, 1.60-2.00 inches.

_Early Stages._--Little is as yet known of these.

The species was first found by Professor Louis Aga.s.siz on the north sh.o.r.e of Lake Superior. It ranges through a rather narrow belt of country, through Quebec, Ontario, and westward to the Rocky Mountains north of the valley of the St. Lawrence and the Great Lakes.

(8) =Colias scudderi=, Reakirt, Plate x.x.xV, Fig. 8, ?; Fig. 9, ?

(Scudder's Sulphur).

_b.u.t.terfly._--The male on the upper side is colored like _C. philodice_, but the black borders are much wider. The fringes are rosy. The female is generally white,--very rarely slightly yellow,--with very pale dark borders, or often without any trace of black on the outer margin of the wings. On the under side the apex of the fore wings and the entire surface of the hind wings are greenish-gray. The discal spot of the secondaries is well silvered and margined with pale red. Expanse, 1.80-2.00 inches.

_Early Stages._--We know but little of these, except that the caterpillar feeds on the leaves of the huckleberry and the willow.

Scudder's Sulphur is found in Colorado, Utah, Montana, and British Columbia.