_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, ♂ (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, ♂ (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, ♀. 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.