[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.
(_a_) Winter form =oleracea-hiemalis=, Harris, Plate x.x.xIV, Fig. 16, ?
(see also p. 5, Fig. 9, and p. 13, Fig. 27). The wings are white above in both s.e.xes. 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 x.x.xIV, 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 x.x.xIV, Fig. 15, ?. 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 =bryoniae=, Ochsenheimer, Plate x.x.xIV, Fig. 17, ?. 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 x.x.xIV, Fig. 19, ?.
This form is larger than the others, and in markings intermediate between _pallida_ and _bryoniae_. The under side in both s.e.xes 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 rapae=, Linnaeus, Plate x.x.xV, Fig. 3, ?; Plate II, Figs. 11, 12, _larva_; Plate V, Figs. 58, 65, _chrysalis_ (The Cabbage-b.u.t.terfly).
_b.u.t.terfly._--This common species, which is a recent importation from Europe, scarcely needs any description. It is familiar to everyone. 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 b.u.t.terflies 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 b.u.t.terfly 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.
+--------------------------------------------------------------+ | | | EXPLANATION OF PLATE x.x.xIV | | | | 1. _Euchloe cethura_, Felder, var. | | _morrisoni_, Edwards, ?. | | 2. _Euchloe creusa_, Dbl.-Hew., ?, | | _under side_. | | 3. _Euchloe ausonides_, Boisduval, ?, | | _under side_. | | 4. _Euchloe sara_, Boisduval, var. _flora_, | | Wright, ?. | | 5. _Euchloe sara_, Boisduval, var. _flora_, | | Wright, ?. | | 6. _Euchloe sara_, Boisduval, var. _julia_, | | Edwards, ?, _under side_. | | 7. _Neophasia menapia_, Felder, ?. | | 8. _Pieris beckeri_, Edwards, ?. | | 9. _Pieris beckeri_, Edwards, ?. | | 10. _Pieris protodice_, Boisd.-Lec., ?. | | 11. _Pieris protodice_, Boisd.-Lec., ?. | | 12. _Pieris sisymbri_, Boisduval, ?. | | 13. _Pieris occidentalis_, Reakirt, ?. | | 14. _Pieris virginiensis_, Edwards, ?. | | 15. _Pieris napi_, Esper, var. _pallida_, | | Scudder, ?. | | 16. _Pieris napi_, Esper, var. _oleracea-hiemalis_, | | Harris, ?. | | 17. _Pieris napi_, Esper, var. _bryoniae_, | | Ochsenheimer, ?. | | 18. _Pieris protodice_, Boisd.-Lec., var. | | _vernalis_, | | Edwards, ?. | | 19. _Pieris napi_, Esper, var. _acadica_, | | Edwards, ?. | | 20. _Kricogonia lyside_, G.o.dart, ?. | | 21. _Kricogonia lyside_, G.o.dart, ?. | | | | [Ill.u.s.tration PLATE x.x.xIV.] | +--------------------------------------------------------------+
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-b.u.t.terfly, fluttering about the place lit on the straw hat of one of the dignitaries. The naturalist, accosting him, said: "Friend, do you know what rests upon your head?" "No," said he. "A b.u.t.terfly."
"Well," said he, "that brings good luck." "Yes," replied the naturalist; "and the insect reveals to me the wonderful instinct with which nature has provided it." "How is that?" quoth the city father. "It is a cabbage-b.u.t.terfly that rests upon your head."
Genus NATHALIS, Boisduval
"The b.u.t.terflies, gay triflers Who in the sunlight sport."
HEINE.
_b.u.t.terfly._--The b.u.t.terfly is very small, yellow, margined with black.
The upper radial vein in the fore wing is wanting. The subcostal has four nervules, the third and fourth rising from a common stalk emitted from the upper outer corner of the cell, the first and second from before the end of the cell. The precostal vein on the hind wing is reduced to a small swelling beyond the base. The palpi are slender; the third joint long and curved; the second joint oval; the third fine, spindle-shaped, and pointed. The antennae are rather short, with a somewhat thick and abruptly developed club.
[Ill.u.s.tration FIG. 142.--Neuration of the genus _Nathalis_, enlarged.]
_Early Stages._--Very little is known of these.
Three species belong to this genus, which is confined to the subtropical regions of the New World, one species only invading the region of which this volume treats.
(1) =Nathalis iole=, Boisduval, Plate x.x.xII, Fig. 21, ?; Fig. 22, ?
(The Dwarf Yellow).
_b.u.t.terfly._--This little species, which cannot be mistaken, and which requires no description, as the plate conveys more information concerning it than could be given in mere words, ranges from southern Illinois and Missouri to Arizona and southern California. Its life-history has not yet been described. Expanse, 1.00-1.25 inch.