Nofes on Seasonal DimorpMtim. 561 



evidently correlated with the leaf-like coloration on the 

 underside in this genus. 



(4.) P. archesia, Cram. = P. pelasgis, God. {= P. 

 cliafpunga, Hew.). The intimate connection between 

 these three forms is much more evident. The conspicu- 

 ous pale stripe of the summer Pelasgis is much darkened 

 and reduced in archesia on both surfaces., the underside 

 assuming the usual leaf-like markings^ and the apices of 

 forewings being strongly falcate. Trimen's var. A of 

 archesia is evidently an intermediate form. I have met 

 with only one example of chajnaiga, which I captured 

 on the 29th December, 1894, in the Maroii Valley in 

 company w-ith pelasgis, and I am convinced that it is 

 nothing but an intermediate form of that insect in the 

 direction of archesia. In the latter the discal band of the 

 hindwings often shows a tendency to break up into rings 

 round the ocelli, as in typical chapunga. Mr. Barker 

 informs me that he has on one occasion taken archesia 

 and pelasgis in copula at Malvern. 



(5.) P. artaxia, Hew. = P. nachtigaHi, Dew. These 

 forms are practically identical on the upperside, but the 

 undersides are very different. Artaxia with its more 

 fulcate forewings and distinctly leaf-like underside, occurs 

 (in Mashunaland at least) only during the drier part of 

 the year, being replaced in December by the smaller P. 

 oiachiigalii, which is darker and clearer below, with the 

 two ocelli of upperside clearly reproduced in the hind- 

 wing. In December, 1895, on two occasions I took a 

 battered 6 of artaxia m copula with a newly emerged 

 9 of nachiigalii. An objection to the amalgamation ot 

 these two forms was suggested to me in the fact that 

 Mr. Selous, collecting between Umtali and the coast 

 during the wet season, never took naclitigalii but only 

 artaxia. I have shown specimens of the former to Mr. 

 Selous, but he asserted that he had never seen the 

 insect. However, while going from Salisbury to Beira, 

 during January, 1896, I kept a careful look out for 

 nachtigalii. The most easterly specimens I captured 

 were two Ss, in very bad condition, on the top of 

 Christmas Pass, near Umtali, on the 14th of January. 

 Beyond that I only observed artaxia, taking a fine newly 

 emerged specimen at Chimiro on the 16th January. If 

 my remarks on the Tiigela group he borne in mind, it 

 will be seen that these tacts do not at all invalidate my 



