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Show 64 MR. R. T R I M E N O N B U T T E R F L I E S [Jan. 20, darkest it is whitish and conspicuous. On the underside, the pattern is in complete agreement with that of the male, except that in all examples there is more or less narrow representation of the whitish subapical bar in the fore wing; but the colouring is always very much duller, varying in accordance with the tint of the upperside, until in the darkest example there remains no trace of the pink colouring observable in the more reddish specimens. I place A. acontias, Westw., as a variety of A. atolmis, because the material (10 male and 7 female examples) afforded by Mr. Eriksson's collection makes its separation-warrantable enough when only a single female example was forthcoming-no longer possible. The males are of a rather less vivid red than the typical male atolmis, the females of similar variable dull reddish-ochreous and ochreous-brown tints to those presented by the typical female atolmis, except that the extreme form of almost ashy brownish-grey with pronounced subapical whitish bar in the fore wing is not among them. The conspicuous distinction from typical atolmis in both sexes is the enlargement of all the black markings, viz. the basal suffusion, the cellular aud discal spots \ the hind-marginal edging (especially in the hind wing), and the clouding of the nervules. In connection with the widening of the hind-marginal edging in the hind wing, the underside presents a distinguishing character (mentioned by Westwood in his description of the female), viz., an additional hind-marginal black line, parallel to and a little before the line actually edging the hind margin. This feature led me at first to think that A. acontius might be kept separate from A. atolmis; but on close examination of all the examples of typical A. atolmis, I found more or less distinct beginnings of the additional black line in no fewer than two males and five females, its most developed condition-that of a very slender line regularly interrupted on the nervules-being in the generally most heavily black-marked of all the twenty males. I think it highly probable that we have in this instance a case of seasonal dimorphism, and that A. acontias is simply the later (or summer) brood of A. atolmis. From the dates furnished by Mr. Eriksson it is clear that typical A. atolmis was captured between 1st August and 30th September, while A. acontias was taken in November and December (14 of the 17 examples between the 20th November and 2nd December). Two of A. acontias-the most heavily-marked male and one of the two most heavily-marked females -were taken in the same locality (Omrora) as the bulk (21 examples) of A. atolmis in the preceding August. Exp. al. ( <S ) 1 in- 9-11^ lin.; ( $ ) 1 in. 9-11 lin. Var. acontias (cJ) 1 in. 10 lin. to 2 in. 1 lin.; ( $ ) 1 in. 10 lin. to 2 in. 1 lin. This species occurs as far to the eastward as the Victoria Falls of the Zambesi, 30 miles to the south of which it was taken by Mr. F. U. Barber (who sent me two typical males and one approaching 1 In the fore wing, of the two additional spots occasionally found in typical atolmis, that on the inner margin is invariably present, but the subbasal one is absent in three of the males and in all the females. |