198 Dr. F. A. Dixcy on 



in a specimen from Gondokoro on the White Nile) is 

 narrower in proportion than the usual scale of P. simana. 

 But there is no doubt that a comparison of the average 

 dimensions of the scent-scales in the two forms shows the 

 distinction above stated. The scent-scale in P. charina is 

 much like that in P. simana, but here again it is on the 

 average shorter, though not so short as that of P. venata 

 (figs. 10, 11, 12). 



It was mentioned on p. 196 that in addition to the dark 

 granular patch of the scent-scale, there was another feature 

 which would seem to indicate that the Voi River and Mlegwa 

 specimens are a form of liliana rather than of simana. 

 This is the presence of a well-marked dark spot on the 

 upper surface of the fore-wing of the female, situated 

 between the median and submedian veins and usually 

 extending into the space below the submedian. The spot 

 in question is characteristic of the wet-season and inter- 

 mediate females of liliana, including the " gerda" form 

 from Mlegwa and the Voi River, but appears to be always 

 absent, or at most only represented by a very slight 

 powdering of dark scales, in the females of charina, simana 

 and venal a. Judged by this criterion, as well as by the 

 evidence of the scent-scales, there appears to be no doubt 

 that the "gerda " forms are rightly associated with liliana 

 and not with simana. 



It may be well here to recapitulate in some detail the'chief 

 points that call for notice in regard to these several forms. 



(1) P. charina, Boisd. — This is the form which is found 

 in Cape Colony, Natal, Zululand, and (probably) the 

 Transvaal. Both males and females are without black 

 veining. The male is nearly always without any dis- 

 cocellular spot on the upper surface, but possesses one on 

 the lower surface of the hind-wing, and occasionally of 

 the fore-wing: the latter, if present, being minute. On 

 the upper surface of the fore- wing of the female the dis- 

 coeellular spot may be present or absent; it appears to 

 be always absent from the hind wing. Beneath, in the 

 female, it is constantly present in the hind-wing and often 

 visible on the fore-wing as well. The upper surface of 

 the male may be entirely immaculate; but on the fore- 

 wing there is usually a dark streak bounding the cost a. 

 and a marginal series of dots on the hind border, which 

 are often discrete, but may be merged into a dark hand 



