PAPILIONIDÆ (THE SWALLOWTAILS AND ALLIES) The butterflies of this family in both sexes are provided with six ambulatory feet. The caterpillars are elongate, and in the genera _Papilio_ and _Ornithoptera_ have osmateria, or protrusive scent-organs, used for purposes of defense. The chrysalids in all the genera are more or less elongate, attached at the anal extremity, and held in place by a girdle of silk, but they never lie appressed to the surface upon which pupation takes place, as is true in the _Erycinidæ_ and _Lycænidæ_. SUBFAMILY PIERINÆ (THE SULPHURS AND WHITES) "Fly, white butterflies, out to sea, Frail pale wings for the winds to try; Small white wings that we scarce can see Fly. Here and there may a chance-caught eye Note, in a score of you, twain or three Brighter or darker of tinge or dye; Some fly light as a laugh of glee, Some fly soft as a long, low sigh: All to the haven where each would be,--Fly." SWINBURNE. _Butterfly._--For the most part medium-sized or small butterflies, white or yellow in color, with dark marginal markings. In many genera the subcostal vein of the fore wing has five, or even in some cases six nervules, and the upper radial is lacking in this wing. _Early Stages._--The eggs are spindle-shaped, marked with vertical ridges and cross-lines. The caterpillars are cylindrical, relatively long, generally green in color, longitudinally striped with darker or paler lines. The chrysalids are generally more or less pointed at the head, with the wing-cases in many of the genera greatly developed on the ventral side, forming a deep, keel-shaped projection upon this surface. +--------------------------------------------------------------+ | | | EXPLANATION OF PLATE XXXIII | | | | 1. _Catopsilia agarithe_, Boisduval, ♂. | | 2. _Catopsilia eubule_, Linnæus, ♂. | | 3. _Catopsilia eubule_, Linnæus, ♂, | | _under side_. | | 4. _Catopsilia philea_, Linnæus, ♂. | | 5. _Colias eurytheme_, Boisduval, ♂, | | _under side_. | | 6. _Pyrameis huntera_, Fabricius, ♂, | | _under side_. | | | | [Illustration PLATE XXXIII.] | +--------------------------------------------------------------+ This subfamily is very large, and is enormously developed in the tropics of both hemispheres. Some of the genera are very widely distributed in temperate regions, especially the genera _Pieris_ and _Colias_. Genus DISMORPHIA, Hübner