_Caterpillar._--The caterpillar is so well delineated in Plate III, Fig. 17, as to obviate the necessity for a lengthy verbal description. _Chrysalis._--What has been said of the caterpillar is also true of the chrysalis (see Plate IV). The larva feeds upon the willow, cherry, apple, linden (_Tilia_), huckleberry, currant, and other allied shrubs and trees. The butterfly is somewhat variable, and a number of varietal forms have been described. It ranges generally over the United States and southern Canada as far as the Rocky Mountain ranges in the West, and is even said to occur at high elevations in Mexico. (2) =Basilarchia arthemis=, Drury, Plate XXII, Fig. 4, ♂, form =lamina=, Fabricius; Fig. 5, ♂, form =proserpina=, Edwards, Plate III, Fig. 26, _larva_; Plate IV, Figs. 14, 23, _chrysalis_ (The Banded Purple). _Butterfly._--Easily distinguished in the form _lamina_ from _astyanax_, which in other respects it somewhat closely resembles, by the broad white bands crossing both the fore wings and the hind wings, and followed on the secondaries by a submarginal row of red spots shading inwardly into blue. In the form _proserpina_ there is a tendency on the part of the white bands to become obsolete, and in some specimens they do entirely disappear. The likeness to _astyanax_ in such cases is striking, and the main point by which the forms may then be discriminated is the persistence of the red spots on the upper side of the secondaries; but even these frequently are obsolete. Expanse, 2.50 inches. _Egg._--The egg is grayish-green, with "kite-shaped" cells. _Caterpillar._--Greenish-or olive-brown, blotched with white in its mature form, which is well represented in Plate III. It feeds upon the willow, the hawthorn (_Cratægus_), and probably other plants. _Chrysalis._--The figure in Plate IV is sufficiently exact to obviate the necessity for further description. This beautiful insect ranges through northern New England and New York, Quebec, Ontario, and the watershed of the Great Lakes, spreading southward at suitable elevations into Pennsylvania. I have taken it about Cresson, Pennsylvania, at an elevation of twenty-five hundred feet above sea-level. It is not uncommon about Meadville, Pennsylvania. The species appears to be, like all the others of the genus, somewhat unstable and plastic, or else hybridization is very frequent in this genus. Probably all the species have arisen from a common stock.