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tint of trimeni. A slight trace of the " tail " is also to be seen 

 in the same specimen. The most specialised of all the mimetic 

 females, cenea, mimetic of Amauris echeria (Plate I, Fig. 5) and 

 Am. alhimaculata (Plate I, Fig. 4) in East Africa, and westward 

 as far as the Eastern borders of the Congo State, also appears 

 to have been directly derived from trimeni. Thus Fig. 4 on 

 Plate II shows us an example with the fully developed cenea 

 pattern, but with all the pale markings retaining the yellowish 

 tint of trimeni. Comparison between Figs. 4 and 6 shows that 

 the hindwing of cenca is easily derived from trimeni by an 

 increase in the breadth of the black border, while the forewing 

 also originated by an increase of black, together with the 

 splitting up of the pale markings into a series of separate 

 spots. The traces of such a process can, in fact, be seen in an 

 initial stage in the outer half of the forewing of the trimeni 

 represented in Fig. 6\ Comparison between Figs. 4 and 5 shows 

 how the ordinary colours of cenea are obtained by a darken- 

 ing into ochreous of the basal part of the hindwing, while 

 all the other markings become white or sometimes ochreous, 

 according as the form mimics varieties of Amauris with white 

 spots or with yellow spots in the forewing. The wonderful 

 mimetic form planemoides, resembling the male of Planema 

 macarista and both sexes of PI. poggei, is also found among 

 the remarkable assemblage of female forms on the Escarpment, 

 although, if either of its models occurs at all in this locality, 

 it must be extremely rare. The planemoides female almost 

 certainly arose in connection with the origin of the cenea form : 

 the hindwing, in fact, is almost precisely cencas, except that the 

 basal patch becomes white like hippocoon instead of ochreous like 

 cenea. In the forewing the pale markings of trimeni are not so 

 completely broken up into separate spots as in the origin of cenea, 

 but form larger areas which gain a rich fulvous tint and fuse 

 together into a band crossing the wing from the costa to the 

 posterior angle. It is exceedingly interesting to find that an 

 ancestral stage in the development of this pattern is to be found, 

 not only in association with the fully formed planemoides, but 

 also in Natal, far south of the range of the Planema models. This 

 ancestral stage of planemoides — the leighi form — indicates very 

 clearly the way in which the forewing band of planemoides arose 



