Cowardice is not one of his attributes, and if he has formed a preference for any especial spot, he will risk loss of liberty and life rather than forsake it.
The old mode of capturing this prize was by a ring net fixed at the end of a pole some twenty or thirty feet long, and so sweeping him off as he sat on his leafy throne, or in one of his evolutions when he quitted his seat for a turn in the air.
This method still is practised, and succeeds occasionally, but the weapon is an unwieldy one, both in use, and for carriage to the place of action; and science has now placed in our power another plan, by means of which I believe that by far the greater number of recent captures have been made.
The plan alluded to, is to take advantage of the creature's royal taste for game—for in that light I take his predilection for decomposing animal matter, now a matter of notoriety; and so potent is the attraction of the haut-goût for the royal palate, that if any animal, or part of one, not too recently slaughtered, be suspended near the known haunts of the insect, ten to one but its savour will bring him down to earth to taste the luxurious morsel, and so engrossed does he become when thus engaged, that he may be swept off by the net without difficulty. In the space of two or three days large numbers of Emperors have been caught by means
of this novel and singular trap, and the seemingly coarse and unbutterfly-like taste that leads them to it.
The wings of the male only have that splendid glow of changing purple that gives him his name and honours, the empress having in its place a sober garb of brown; she, however, considerably exceeds her lord in dimensions and expanse of wing. From her stay-at-home habits, sitting all day in her oak-leaf bower, she is comparatively seldom seen or captured. I believe collectors generally take about ten males to one female.
On the under side the colouring of both sexes is similar, and affords a striking contrast to the dark upper surface, having the white markings arranged as on the upper side, but rather broader; and, instead of the dark brown or purple, a lively pattern of orange-brown, greyish brown, and black. On the front wing is a purple-centred eye-spot, and a smaller one is seen near the lower angle of the hind wing.
The firm, muscular appearance of the wings, gives promise of great strength in those organs, fully borne out in the powerful and bird-like flight of the creature, who has also a habit of soaring, about midday, to vast heights in the air, and there engaging in contests, sportive or pugnacious, with his brother, or rival, Emperors.
In the caterpillar state also the Purple Emperor is a remarkable creature, of the form shown in [Plate I]. fig. 5, bright green, striped with yellow on each side, and bearing on his head a pair of horns or tentacles.
Though the perfect insect is chiefly found on the oak, the caterpillar feeds generally on the broad-leaved Sallow, though it has been occasionally found on the Poplar.