( ^v ) 



formerly looked upou as one of the rarest of African 

 butterflies, and that until the recent arrival of material 

 collected by Mr. Neave not a single example of it existed 

 in the national collection. There was almost more a pi'iori 

 reason for regarding this butterfly as a Batesian mimic of 

 Danaida (Limnas) chrysijjpus, L., than any other. Yet this 

 is the very species which Mr. Byatt * observed in 1905 to 

 exist in a proportion of nearly 5 per cent, of its model in 

 a large consignment collected indiscriminately by natives at the 

 sources of the Congo, and the species which Mr. S. A. Neave 

 now finds to be by far the most abundant as well as the 

 boldest Pseudacrssa in the forests of the Congo Free State 

 in which he has collected. The part of his letter bearing 

 on this question and on the species of CrevAs and their 

 mimics is as follows : — 



" Kambove, Congo Free State, 



''November lUh, 1907. 



"Since I last wrote to you I have been out to and just 

 returned from the country to the west of this place — an 

 extremely interesting country, and I wish I had had moi'e 

 time there. I took a large number of remarkable Lepidoptera. 

 Diurnal moths were most abundant in great variety, and of 

 extraordinary coloration. I have not, I am sorry to say, met 

 again with the big mimetic Pseudacrsea, although the Aletis 

 models have been plentiful. Mimacrxa marshalli, Trim., and 

 Pseudacrxa poggei were just beginning to reappear at the end 

 of October, and I have taken one of each. Hypolimnaa 

 misippus, L., has also appeared in small numbers. I still 

 think P. poggei the best mimic of Danaida (Limnas) chrgsippus, 

 even better than misijjpus — its flight is so extraordinarily 

 like that of the model. It is rather, I think, a significant 

 fact that of all the Pseudacrxas I have met with (5 sj)]).) jjoggei 

 is by far the most abundant ; while it is bold, and not afraid 

 to expose itself on the wing. I have taken a single specimen 

 of a small species of Pseudacrsea of the boisduvali group which 

 I do not know. 



" I can now give you a little more interesting information 

 * Trans. Eut. Soc. Lond., 1905, p. 264. 



