"Bedouins of the pathless air."—H.H.

Butterfly.—The butterflies belonging to this family are generally quite small, with stout bodies, the thorax strongly developed in order to accommodate the muscles of flight. They are exceedingly rapid in their movements. Both sexes possess six feet adapted to walking, and the tibiÆ of the hind feet, with few exceptions, have spurs. The lower radial vein of the hind wing in many of the genera is lacking, or is merely indicated by a fold in the wing. There is great variety in the form as well as in the coloration of the wings.

Egg.—The eggs, so far as we are acquainted with them, may be said to be, almost without exception, more or less hemispherical, with the flat section of the hemisphere serving as the base. They are sometimes smooth, but not infrequently ornamented with raised longitudinal ridges and cross-lines, the ornamentation in some cases being very beautiful and curious.

Caterpillar.—The caterpillars are cylindrical, smooth, tapering forward and backward from the middle, and generally possess large globular heads. They commonly undergo transformation into chrysalids which have an anal hook, or cremaster, in a loose cocoon woven of a few strands of silk.

This family, the study of which presents more difficulties than are presented by any other family of butterflies, is not very well developed in the PalÆarctic Region, but finds its most enormous development in the Nearctic and Neotropical Regions. It is also very strongly developed in the Indo-Malayan and Ethiopian Regions. There are, at the present time, in the neighborhood of two thousand species belonging to this family which have been named and described.