Ranges from Colorado to California at suitable elevations among the mountains.
Family PAPILIONIDÆ
(The Swallow-tails and Allies).
The butterflies of this group are provided in both sexes with six legs adapted to walking. The internal vein of the hind wing is wanting, its place being taken by the submedian. Caterpillars elongate, and in the genus Papilio provided with osmateria or protrusive forking scent-organs, which, when excited, they thrust forth from the pouch back of the head in which they usually lie concealed. Chrysalids in all the genera more or less elongate, attached at anal extremity to a button of silk, and held in place by a silk girdle, but never closely appressed to the supporting surface as is the case in the Erycinidæ and Lycænidæ.
Subfamily PIERINÆ
(The Yellows, Sulphurs, and Whites).
For the most part small or medium-sized butterflies, white or yellow in color, with dark marginal markings. The eggs are spindle-shaped, marked with vertical ridges and horizontal cross-lines. The caterpillars are cylindrical, relatively long, generally green in color, with longitudinal stripes. The chrysalids are more or less pointed at the head, with the wing-cases greatly developed on the ventral side, forming a more or less keel-shaped projection upon this surface.
The subfamily is very large, and is well represented in the tropics of both the eastern and western hemispheres. Certain genera are also widely distributed in the colder regions of both the north and the south, among them the genus Colias, species of which occur from Greenland to Patagonia and from the North Cape to the Cape of Good Hope.
Genus TACHYRIS Wallace
(The Florida White).
PL. XCV
There are about seventy species in this genus, all of which are found in the Old World, except the one which occurs in our fauna, and which has a very wide range throughout the tropics of the New World.