them. In certain cases it may happen that the moth is more abundant than the Pierine that it resembles^[12].

Tropical Africa is probably more wealthy in mimetic analogies than Indo-Malaya, and the African cases have recently been gathered together by Eltringham in a large and beautifully illustrated memoir^[13]. The principal models of the region are furnished by the Danainae and the allied group of the Acraeinae. Of the Danaines one well-known model, Danais chrysippus,

is common to Africa and to Indo-Malaya. Common also to the two regions are the mimics, Argynnis hyperbius and Hypolimnas misippus (cf. Pl. IV, figs. 3 and 7). The case of the last named is peculiarly interesting because it presents well-marked varieties which can be paralleled by similar ones in D. chrysippus. In addition to the typical form with the dark tipped fore wing relieved by a white bar there is in each species a form uniformly brown, lacking both the dark tip and the white bar of the fore wing. There is also another form in the two species in which the hind wing is almost white instead of the usual brown shade. In both species, moreover, the white hind wing may be associated either with the uniformly brown fore wing or with the typical form. There is also another common African butterfly, Acraea encedon, in which these different patterns are closely paralleled (cf. Pl. IX). Several other species of butterflies and a few diurnal moths bear a more or less close resemblance to D. chrysippus.

Danaine butterflies with the dark interlacing fines on a pale greenish-blue ground, so characteristic of the Oriental region, are represented in Africa by the species Danais petiverana (Pl. VI, fig. 1) ranging across the continent from Sierra Leone to British East Africa. A common Papilio, P. leonidas (Pl. VI, fig. 2) has a similar extensive range, and has been regarded as a mimic of the Danaine. In S. Africa P. leonidas is represented by the variety brasidas in which the white spots are reduced and the blue-green ground is lacking. Brasidas bears a strong resemblance to the tropical

Danaine Amauris hyalites (Pl. VI, fig. 3) of which it has been regarded as a mimic. It must however be added that it is only over a small part of their respective ranges, viz. in Angola, that the two species are to be met with together.

The butterflies belonging to the genus Amauris are among the most abundant and characteristic Danaine models of Africa. Some of the black and white species such as A. niavius (Pl. VIII, fig. 6) are conspicuous insects in a cabinet. Others again, such as A. echeria (Pl. VIII, fig. 7), are relatively sombre-looking forms. Among the best known mimics of the genus is a species of Hypolimnas^[14]—H. dubius. This interesting form is polymorphic and mimics different species of Amauris. The variety wahlbergi, for example, is very like A. niavius, while mima strongly resembles A. echeria (Pl. VIII, figs. 8 and 9). It was at one time supposed that these two varieties of Hypolimnas dubius were different species and the matter was only definitely settled when the two forms were bred from the eggs of the same female. Other mimics of Amauris are found among the Papilios and the Nymphaline genus Pseudacraea.

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