Part 49 (1/2)

[Ill.u.s.tration FIG. 141.--Neuration of the genus _Pieris_.]

(1) =Pieris monuste=, Linnaeus, Plate x.x.xV, Fig. 1, ?; Fig. 2, ? (The Great Southern White).

_b.u.t.terfly._--The upper side of the wings, depicted in the plate, requires no comment. On the under side the black marginal markings of the primaries reappear as pale-brown markings. The hind wing is pale yellow or grayish-saffron, crossed by an ill-defined pale-brown transverse band of spots, and has the veins marked with pale brown, and interspersed between them pale-brown rays on the inters.p.a.ces.

_Early Stages._--What we know of these is derived princ.i.p.ally from Abbot through Boisduval, and there is opportunity here for investigation.

The species has a wide range through tropical America, and is not uncommon in the Gulf States.

(2) =Pieris beckeri=, Edwards, Plate x.x.xIV, Fig. 8, ?; Fig. 9, ?

(Becker's White).

_b.u.t.terfly._--This species, through the green markings of the under side of the hind wings, concentrated in broad blotches on the disk, recalls somewhat the species of the genus _Euchloe_, and by these markings it may easily be discriminated from all other allied species.

_Early Stages._--These have been in part described by Edwards in the second volume of ”The b.u.t.terflies of North America.”

The species ranges from Oregon to central California, and eastward to Colorado.

(3) =Pieris occidentalis=, Reakirt, Plate x.x.xIV, Fig. 13, ? (The Western White).

_b.u.t.terfly._--Not unlike the preceding species on the upper side, but easily distinguished by the markings of the under side of the wings, which are not concentrated in blotches, but extend as broad longitudinal rays on either side of the veins from the base to the outer margin.

_Early Stages._--These require further investigation. We do not, as yet, know much about them.

The species has a wide range in the mountain States of the West, where it replaces the Eastern _P. protodice_.

(4) =Pieris protodice=, Boisduval and Leconte, Plate x.x.xIV, Fig. 10, ?; Fig. 11, ?; Plate II, Fig. 7, _larva_; Plate V, Figs. 66, 67, _chrysalis_ (see also p. 12, Fig. 26) (The Common White).

_b.u.t.terfly._--Allied to the foregoing species, especially to _P.

occidentalis_; but it may always be quickly distinguished by the pure, immaculate white color of the hind wings of the male on the under side, and by the fact that in the female the hind wings are more lightly marked along the veins by gray-green.

Winter form =vernalis=, Edwards, Plate x.x.xIV, Fig. 18, ?. What has been said of the typical or summer form does not hold true of this winter form, which emerges from chrysalids which have withstood the cold from autumn until spring. The b.u.t.terflies emerging from these are generally dwarfed in size, and in the males have the dark spots on the upper side of the wings almost obsolete or greatly reduced, and the dark markings along the veins on the under side well developed, as in _P.

occidentalis_. The females, on the contrary, show little reduction in the size and intensity of any of the spots, but rather a deepening of color, except in occasional instances.

_Early Stages._--The life-history of this insect has often been described. The caterpillar feeds upon cruciferous plants, like many of its congeners.

It ranges from the Atlantic to the Rocky Mountains, from Canada to the Gulf States.

(5) =Pieris sisymbri=, Boisduval, Plate x.x.xIV, Fig. 12, ? (The California White).

_b.u.t.terfly._--Smaller in size than the preceding species, with the veins of the fore wing black, contrasting sharply with the white ground-color. All the spots are smaller and more regular, especially those on the outer margin of the fore wing, giving the edge an evenly checkered appearance. On the under side the hind wings have the veins somewhat widely bordered with gray, interrupted about the middle of the wing by the divergence of the lines on either side of the veins in such a way as to produce the effect of a series of arrow-points with their barbs directed toward the base. The female is like the male, with the markings a little heavier. A yellow varietal form is sometimes found.

_Early Stages._--The life-history is given and ill.u.s.trated by Edwards in his second volume. The caterpillar, which is green, banded with black, feeds upon the _Cruciferae_.

(6) =Pieris napi=, Esper, Plate II, Figs. 8, 9, _larva_; Plate V, Figs.

57, 63, 64, _chrysalis_ (The Mustard White).

_b.u.t.terfly._--This is a Protean species, of which there exist many forms, the result of climatic and local influences. Even the larva and chrysalis show in different regions slight microscopic differences, for the influences which affect the imago are operative also in the early stages of development. The typical form which is found in Europe is rarely found in North America, though I have specimens from the northern parts of the Pacific coast region which are absolutely indistinguishable from European specimens in color and markings. I give a few of the well-marked forms or varieties found in North America to which names have been given.