This family is distinguished from others by the fact that _the males have four ambulatory or walking feet, while the females have six such feet. The antennæ are relatively longer than in the Lycænidæ._ The butterflies belonging to this great group are mostly confined to the tropics of the New World, and only a few genera and species are included in the region covered by this volume. They are usually quite small, but are colored in a bright and odd manner, spots and checkered markings being very common. Many are extremely brilliant in their colors. _The caterpillars are small and contracted. Some are said to have chrysalids which are suspended; others have chrysalids girdled and attached at the anal extremity, like the Lycænidæ. The butterflies in many genera have the habit of alighting on the under side of leaves, with their wings expanded._ The LYCÆNIDÆ, the "Gossamer-winged Butterflies." This great family comprises the butterflies which are familiarly known as the "hair-streaks," the "blues," and the "coppers." _The males have four and the females six walking feet. The caterpillars are small, short, and slug-shaped. The chrysalids are provided with a girdle, are attached at the end of the abdomen, and lie closely appressed to the surface upon which they have undergone transformation._ Blue is a very common color in this family, which includes some of the gayest of the small forms which are found in the butterfly world. _In alighting they always carry their wings folded together and upright._ The PAPILIONIDÆ, the "Swallowtails" and their allies. These butterflies _have six walking feet in both sexes. The caterpillars are elongate, and in some genera provided with osmateria, or protrusive organs secreting a powerful and disagreeable odor. The chrysalids are elongate, attached at the anal extremity, and held in place by a girdle of silk, but not closely appressed to the surface upon which they have undergone transformation._ The HESPERIIDÆ, or the "Skippers." They are generally _small in size, with stout bodies, very quick and powerful in fight. They have six walking feet in both sexes. The tibiæ of the hind feet, with few exceptions, have spurs. The caterpillars are cylindrical, smooth, tapering forward and backward from the middle, and generally having large globular heads. For the most part they undergo transformation into chrysalids which have a girdle and an anal hook, or cremaster, in a loose cocoon, composed of a few threads of silk_, and thus approximate the moths in their habits. The genus _Megathymus_ has the curious habit of burrowing in its larval stage in the underground stems of the yucca. To one or the other of these five families all the butterflies, numbering about six hundred and fifty species, which are found from the Rio Grande of Texas to the arctic circle, can be referred.