the primaries is straight, the outer margin of the secondaries more or less evenly rounded.

Egg. The egg is spindle-shaped, with vertical raised ridges. Caterpillar.-Elongate, the head hemispherical, very slightly, if at all, larger in diameter than the body. The caterpillars feed upon cruciferous plants.

At the

Chrysalis.-Attached by the anal extremity, and held in place by a silk girdle; slightly concave on the ventral side; convex on the dorsal side, with a distinct or pointed hump-like projection on the thorax. point where the thoracic and abdominal segments unite in some species there is in addition a distinct keel-shaped eminence, and at the head the chrysalis is furnished with a short conical projection.

(1) Pieris monuste, Linnæus, Plate XXXV, Fig. 1, ô; Fig. 2, 9 (The Great Southern White).

FIG. 141.-Neuration of the genus Pieris.

Butterfly.—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 interspaces.

Early Stages.-What we know of these is derived principally 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 XXXIV, Fig. 8, 8; Fig. 9, (Becker's White).

Butterfly. 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 Euchloë, 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 Butterflies of North America."

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

(3) Pieris occidentalis, Reakirt, Plate XXXIV, Fig. 13, (The Western White).

Butterfly.-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 XXXIV, Fig. 10, ; Fig. 11, 9; Plate II, Fig. 7, larva; Plate V, Figs. 66, 67, chrysalis (see also p. 12, Fig. 26) (The Common White).

Butterfly.-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 XXXIV, Fig. 18, 3. 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 butterflies 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 XXXIV, Fig. 12, 8 (The California White).

Butterfly.-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 illustrated by Edwards in his second volume. The caterpillar, which is green, banded with black, feeds upon the Cruciferæ.

(6) Pieris napi, Esper, Plate II, Figs. 8, 9, larva; Plate V, Figs. 57, 63, 64, chrysalis (The Mustard White).

Butterfly.-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.

(a) Winter form oleracea-hiemalis, Harris, Plate XXXIV, Fig. 16, 8 (see also p. 5, Fig. 9, and p. 13, Fig. 27). The wings are white above in both sexes. Below the fore wings are tipped with pale yellow, and the entire hind wing is yellow. The veins at the apex of the fore wings and on the hind wings are margined with dusky. (b) Aberrant form virginiensis, Edwards, Plate XXXIV, Fig. 14, . The wings are white above, slightly tipped at the apex of the fore wings with blackish. Below the wings are white, faintly, but broadly, margined with pale dusky.

(c) Form pallida, Scudder, Plate XXXIV, Fig. 15, 9. In this form the wings are white above and below, with a small black spot on the fore wing of the female above, and hardly any trace of dark shading along the veins on the under side.

(d) Alpine or arctic form bryoniæ, Ochsenheimer, Plate XXXIV, Fig. 17, 9. In this form, which is found in Alaska,

Siberia, and the Alps of Europe, the veins above and below are strongly bordered with blackish, and the ground-color of the hind wings and the apex of the fore wings on the under side are distinctly bright yellow.

(e) Newfoundland variety acadica, Edwards, Plate XXXIV, Fig. 19, . This form is larger than the others, and in markings intermediate between pallida and bryonia. The under side in both sexes and the upper side in the female are distinctly yellowish.

Early Stages.-These are well known and have often been described, but some of the varietal forms need further study.

The species ranges from the Atlantic to the Pacific, and from Alaska to the northern limits of the Gulf States.

(7) Pieris rapæ, Linnæus, Plate XXXV, Fig. 3, 9; Plate II, Figs. 11, 12, larva; Plate V, Figs. 58, 65, chrysalis (The Cabbage-butterfly).

Butterfly.-This common species, which is a recent importation from Europe, scarcely needs any description. It is familiar to every one. The story of its introduction and the way in which it has spread over the continent has been well told by Dr. Scudder in the second volume of "The Butterflies of New England," p. 1175. The insect reached Quebec about 1860. How it came no man knows; perhaps in a lot of cabbages imported from abroad; maybe a fertile female was brought over as a stowaway. At all events, it came. Estimates show that a single female of this species might be the progenitor in a few generations of millions. In 1863 the butterfly was already common about Quebec, and was spreading rapidly. By the year 1881 it had spread over the eastern half of the continent, the advancing line of colonization reaching from Hudson Bay to southern Texas. In 1886 it reached Denver, as in 1884 it had reached the head waters of the Missouri, and it now possesses the cabbage-fields from the Atlantic to the Pacific, to the incalculable damage of all who provide the raw material for sauer-kraut. The injury annually done by the caterpillar is estimated to amount to hundreds of thousands of dollars.

INSTINCT

Two city fathers were standing in the market-place beside a pile of cabbages. A naturalist, who was their friend, came by. As he approached, a cabbage-butterfly, fluttering about the place,