Butterfly.—This subfamily is composed for the most part of species of moderate size, though a few are quite large. The fore wings are invariably greatly lengthened and are generally at least twice as long as broad. The hind wings are relatively small, rounded, and without tails. The wings in many of the genera are transparent. The extremity of the abdomen in both sexes extends far beyond the margin of the hind wings, but in the female not so much as in the male. The antennæ are not clothed with scales, and are very long and slender, with the club also long and slender, gradually thickening to the tip, which is often drooping. The fore legs are greatly atrophied in the males, the tibia and tarsi in this sex being reduced to a minute knob-like appendage, but being more strongly developed in the females.
The life-history of none of the species reputed to be found in our fauna has been carefully worked out. The larvæ are smooth, covered in most genera with longitudinal rows of conical prominences.
The chrysalids are said to show a likeness to those of the Euplœinæ, being short, thick, and marked with golden spots. Some authors are inclined to view this subfamily as merely constituting a section of the Euplœinæ. The insects are, however, so widely unlike the true Euplœinæ that it seems well to keep them separate in our system of classification. In appearance they approach the Heliconians more nearly than the Euplœids. Ithomiid butterflies swarm in the tropics of the New World, and several hundreds of species are known to inhabit the hot lands of Central and South America. But one genus is found in the Old World, Hamadryas, confined to the Australian region. They are protected like the Euplœids and the Heliconians. In flight they are said to somewhat resemble the dragon-flies of the genus Agrion, their narrow wings, greatly elongated bodies, and slow, flitting motion recalling these insects, which are known by schoolboys as "darning-needles."
Three genera are said to be represented in the extreme southwestern portion of the United States. I myself have never received specimens of any of them which indisputably came from localities within our limits, and no such specimens are found in the great collection of Mr. W.H. Edwards, which is now in my possession. A paratype of Reakirt's species, Mechanitis californica, is contained in the collection of Theodore L. Mead, which I also possess. Mr. Mead obtained it from Herman Strecker of Reading, Pennsylvania. Reakirt gives Los Angeles as the locality from which his type came; but whether he was right in this is open to question, inasmuch, so far as is known, the species has not been found in that neighborhood since described by Reakirt.
Genus MECHANITIS, Fabricius
Butterfly.—Butterflies of moderate size, with the fore wings greatly produced, the inner margin bowed out just beyond the base, and deeply excavated between this projection and the inner angle. The lower discocellular vein in the hind wings is apparently continuous with the median vein, and the lower radial vein being parallel with the median nervules, the median vein has in consequence the appearance of being four-branched. The submedian vein of the fore wings is forked at the base. The costal margin of the hind wings is clothed with tufted erect hairs in the male sex. The fore legs of the male are greatly atrophied, the tarsi and the tibia being fused and reduced to a small knob-like appendage. The fore legs of the female are also greatly reduced, but the tarsi and tibia are still recognizable as slender, thread-like organs.
[a]Fig. 80.]—Neuration of the genus Mechanitis. The letters refer to the names of the veins. (See Fig 40.)
The caterpillars are smooth, cylindrical, ornamented with rows of short fleshy projections.
The chrysalids are short and stout, suspended, and marked with golden spots.