Note 15 — Chapter III

But among all the mimics of Danaines in Africa and elsewhere Papilio dardanus is pre-eminent, and has been described by more than one writer as the most important case of mimicry in existence. Not only does it shew remarkable resemblances to various Danaids, but it presents features of such peculiar interest that it must be considered in more detail. Papilio dardanus in its various sub-races is spread over nearly all the African continent south of the Sahara. Over all this area the male, save for relatively small differences, remains unchanged—a lemon-yellow insect, tailed, and with black markings on fore and hind wings (Pl. VIII, fig. 1). The female, however, exhibits an extraordinary range of variation. In South Africa she appears in three guises, (1) the cenea form resembling Amauris echeria, (2) the hippocoon form like Amauris niavius, and (3) the trophonius form which is a close mimic of the common Danais chrysippus[15]. Except that cenea does not occur on the West Coast these three forms of female are found over almost all the great continental range of dardanus and its geographical races. Northwards in the latitude of Victoria Nyanza occurs a distinct form of female, planemoides, which bears a remarkable resemblance to the common and distasteful Planema poggei, and is found only where the latter is abundant. All of these four forms are close mimics of a common Danaine or Acraeine model. Other forms of female, however, are known, of which two, dionysus and trimeni, are sufficiently distinct and constant to have acquired special names. Dionysus may be said to unite the fore wing of the hippocoon form with the hind wing of the trophonius form, except that the colour of the last part is yellow instead of bright brown. It is a western form and is unlike any model. Trimeni also is unlike any model but is of peculiar interest in that it is much more like the male with its pale creamy-yellow colour and the lesser development of black scales than occurs in most of the forms of female. At the same time the general arrangement of the darker markings is on the whole similar to that in the hippocoon and in the trophonius form. Trimeni is found on the Kikuyu Escarpment, near Mt Kenia, along with the four mimicking forms.