THE SWALLOW-TAILED BUTTERFLY. (Papilio Machaon.)
([Plate III]. fig. 1.)
There is no possibility of mistaking this noble insect for any other of our native species, after a glance at its portrait. Its superior size, conjoined with the possession of a pair of long tails on the hind wings, would at once mark it distinctly, independently of the peculiar markings and colour.
In the colouring of the wings, a broad simplicity prevails, the general ground-tint being a clear creamy yellow, with the bars and marginal bands of the deepest velvety black. The broad bands of black on the front wings are powdered towards the centre with yellow scales, and those on the hind wings with blue scales. The only other colour on this side is a spot of rust-red at the inner angle of the hind wings.
The under side is very similar in colouring to the upper, but the black markings are less decided and sharp, and there are several additional rust-red spots on the hind wings.
The caterpillar, which is a very handsome creature, is found feeding on various umbelliferous plants; among which, its chief favourites in this country appear to be the Wild Carrot (Daucus Carota), the Marsh Milk-parsley (Selinum palustre), and Fennel (Anethum Fœniculum). In colour it is bright green, with velvet-black rings, which are spotted with red. A distinguishing mark of this caterpillar is a reddish-coloured forked appendage just behind its head, which, when the animal is alarmed, gives out a strong-scented fluid, supposed to be for the purpose of alarming some of its enemies.
The chrysalis, again, is a very pretty object, especially when of its ordinary colour, which is a lively green, shaded in some parts into bright yellow; but there is a frequent variety marked only with various shades of brown and buff. Living specimens of both of these are before me at this moment, and when they assume the perfect state, I shall be curious to mark whether these differences are continued in the respective butterflies.
These chrysalides are most interesting objects to keep during the winter months. As the spring advances, the colours of the butterfly begin to appear faintly through their thin green envelope, and the pattern of the upper wings, which only are visible, becomes at last distinctly perceptible, of course in miniature. When this is the case, we should begin to watch for the release of the beautiful prisoner.
If you visit his cage the first thing every morning (for his exit most frequently takes place in the early part of