_Caterpillar._--The caterpillar, in its mature stage, is relatively long, with the head small. _Chrysalis._--With the head relatively enormously projecting; wing-cases compressed, and uniting to form a conspicuous keel-shaped projection, the highest point of which lies at the juncture of the two ends of the silk girdle where they are attached to the supporting surface. There are numerous species of this genus, and all are exceedingly pretty. (1) =Euchloë sara=, Boisduval, Plate XXXII, Fig. 28, ♂; Fig. 29, ♀ (Sara). _Butterfly._--The wings on the upper side in both sexes are shown in the figures above cited. On the under side the hind wings are marked with dark irregular patches of greenish-brown scales loosely scattered over the surface, and having a "mossy" appearance. There are several forms which are regarded by recent writers as varieties and may probably be such. Of these we give the following: (_a_) Variety =reakirti=, Edwards, Plate XXXII, Fig. 31, ♂; Fig. 32, ♀ (Reakirt's Orange-tip) =flora=, Wright, Plate XXXIV, Fig. 4, ♂; Fig. 5, ♀. This form hardly differs at all from the form _sara_, except in being smaller, and having the margins of the hind wings marked with dark spots at the ends of the veins. (_b_) Variety =Stella=, Edwards, Plate XXXII, Fig. 35, ♂; Fig. 36, ♀ (Stella). The females of this form are prevalently yellowish on the upper side of the wings; otherwise they are marked exactly as the preceding variety. (_c_) Variety =julia=, Edwards, Plate XXXII, Fig. 34, ♂; Plate XXXIV, Fig. 6, ♀, _under side_ (Julia). The only distinction in this form is the fact that the black bar dividing the red apical patch from the white on the remainder of the wing is broken, or tends to diminution at its middle. _Early Stages._--Unknown. The species, in all its forms, belongs to the mountain States of the Pacific coast. _Flora_, Wright, is regarded by Beutenmüller, who has given us the latest revision of the genus, as identical with _sara_. It comes nearer the variety _reakirti_ than any other form, as will be seen by an examination of the plates which give figures of the types. Expanse, 1.25-1.75 inch. (2) =Euchloë ausonides=, Boisduval, Plate XXXII, Fig. 24, ♂; Fig. 25, ♀; Plate XXXIV, Fig. 3, ♂, _under side_ (Ausonides). _Butterfly._--On the under side the fore wings are greenish; the hind wings are marked with three irregular green bands, the outer one forking into six or seven branches toward the outer and inner margins. Expanse, 1.65-1.90 inch. _Early Stages._--The larva and chrysalis are described by Edwards in "The Butterflies of North America," vol. ii. The caterpillar is pale whitish-green, with dark-green longitudinal stripes on the side and back. It feeds on cruciferous plants. _Ausonides_ ranges from Arizona to Alaska, and eastward to Colorado. (3) =Euchloë creusa=, Doubleday and Hewitson, Plate XXXII, Fig. 23, ♂; Plate XXXIV, Fig. 2, ♀, _under side_ (Creusa).