64 MR. R. TRIMEN ON BUTTERFLIES [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 observahle in the more reddish specimens. 



I place A. acontias, Westw., as a variety of A. atoltnis, 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 (men- 

 tioned 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. acontias 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 aud 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 ex- 

 amples) of A. atolmis in the preceding August. 



Exp. al. ( (S) I in. 9-1 Ig liu. ; ( 5 ) 1 in. 9-11 lin. Var. acontias 

 ( c? ) 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 



^ 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. 



