Papilio dardanus (merope) and Acrxa johnstoni. 297 
forms. Every one of the six polytrophus cenca which 
have come under my observation are primitive in the tint 
of the pale markings and we must assume that in this 
case we are in presence of a truly ancestral feature. 
(€) An interesting gynandromorphic specimen of the § f. 
planemoides. 
Although the male and the diverse female forms of the 
southern P. dardanus—the sub-species cenea—have been 
shown by direct evidence to be a single species by the 
important breeding experiments of Mr. G. F. Leigh, F.1.S.,* 
the same proof is unfortunately still wanting in other 
parts of Africa. It is therefore very satisfactory that other 
evidence has become available in the case of the most 
recently discovered form planemoules. This is in part 
supplied by the existence of intermediates between it and 
the other female forms of dardanus, two of which are 
shown on Figs. 1 and 3 on Plate XX. But still more 
striking evidence is supplied by a remarkable gynandro- 
morphic specimen collected by Mr. T. T. Behrens, R.E., 
and represented on Plate XVIII, Fig. 4. The butterfly 
was obtained in 1902-3 on the west shore of the Victoria 
Nyanza between Entebbe and the mouth of the Kageru 
River. The admixture of male colouring, which is con- 
fined to the left wings, is very well represented in the 
figure, except upon the white patch of the hind-wing, where 
the pale yellow streaks could not be differentiated from 
the white background by photographic means. If the 
black ground colour of the left hind-wing be compared 
with that of the right, it is seen that three submarginal 
irregular areas of a deeper shade are present on the former 
wing but absent from the latter. These represent the sub- 
marginal band of the male while the spaces between them 
are the costal and inner gaps. The yellow male scales 
pass through the costal gap as an almost continuous 
streak, while they are developed in small scattered masses 
in the neighbourhood of the inner gap. The yellow 
scales reach the extreme margin of the hind-wing in the 
concavities of the scalloped border, as in the male, while 
the yellow of the two concavities nearest the anal angle 
* Published in Trans. Ent. Soc. 1904, p. 677, and in the present 
memoir, 
