The hind wing is deeply mottled with ferruginous, on which the lighter white markings stand forth very conspicuously.
The median vein in the hind wing has three nervules as in the fore wing.
In many species there is a tailed projection or two on the hind inner margin of the hind wing.
The hind wing is tailed at the end of the third median nervule.
Fig. 9, A, shows a fore and a hind wing of the Swallow-tail butterfly.
The cell of the hind wing is evenly rounded at its outer extremity.
Spread the wings of the adult and make a careful drawing of one front and one hind wing showing accurately the wing veins.
On the front edge of the hind wing a short distance from the outer end is a row of hooks.
There is also another form in the two species in which the hind wing is almost white instead of the usual brown shade.
The margins are all black, and inside the broader margin of the hind wing is a row of six very pale yellow spots.