BEDROCK 



rare among the female forms of dardanus. The explanation is 

 almost certainly to be found in the conspicuous black-and-white 

 pattern which makes dominicanus one of the most striking and 

 easily remembered of all African butterflies. The comparison of 

 Fig. 2 with 4 and 5, will at once suggest that dominicanus forms a 

 far more striking feature in a forest than a much larger number of 

 echeria and albimaculata . 



With probable exceptions here and there in special localities where 

 dominicanus is wanting or rare, the proportions of the three forms 

 remain about the same up the east coast into British East Africa.. 

 and westward into the Uganda Protectorate. On the eastern shores 

 of the Victoria Nyanza, however, A. dominicanus meets and becomes 

 transitional into the western species A. niacins, with a smaller white 

 patch (Plate III., Fig. 1), and west of the great lake we find hippocoon 

 with a correspondingly reduced patch. A. echeria and its ally are 

 very abundant in the Uganda forests, but somewhere west of the 

 Protectorate they disappear, and when the coast is reached, and 

 no doubt far into the interior as well, the cenea form is unknown, 

 although hippocoon remains abundant and trophonius rare. 



A new female form appears on the east of the Victoria Xyanza, 

 becomes fairly common on the west of the lake, where it is probably 

 next to hippocoon in abundance, appears on the west coast in Angola, 

 and almost certainly occurs over the intervening area. This is the 

 planemoides form recently described by Trimen, and it is of great 

 interest inasmuch as its models are Acraeine and not Danaine. One 

 of its two models, the male of Planema macarista, was represented 

 in Fig. 6 on the plate facing p. 58 of the first number of Bedrock 

 (April, 1912). The male and female of its second model PL poggei are 

 so similar to the male of macarista that the same figure gives a good 

 idea of their general appearance. It is interesting to note in passing 

 that these Planemas, with their striking pattern, were selected for 

 illustration and description in the earlier article because of the 

 influence which they exert upon the females of an Acrcea, viz., upon 

 a mimic remote from the Papilioninoe, to which dardanus belongs. 

 Equally clear examples of their influence in still other groups could 

 be described if space permitted. Any hypothesis which aims to 

 interpret the phenomena of mimicry must take into account the 

 fact that the influence of a striking dominant model commonly 



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