( ex ) 



these are in nine cases out of ten objectionable), where you 

 could state, as fully as your materials permit, all the facts 

 about similar varieties pairing — at a guess how many you 

 caught, and how many now in your collection 1 I look at this 

 fact as very important ; if not in your book, put it somewhere 

 else, or let me have cases." ^ 



Remembering that Mr, Roland Trimen, F.R.S., had expressed 

 the same opinion as the result of his wide and long experience 

 of South African butterflies, I asked him if he would kindly 

 furnish me with a statement. His reply, dated Dec. 28, 1903, 

 is as follows : — 



"Dec. 28, 1903. 



"I have noticed the tendency of the sexes of a variety to 

 pair together rather than with other varieties in the numerous 

 cases of captured pairs sent to me by correspondents in South 

 Africa, and sometimes in cases of the same kind which occurred 

 to myself when collecting. The species which particularly 

 attracted my notice in this way during my visit to Natal was 

 nyjianis acheloia ( = G'utzius, Herbst, part), which is curiously 

 variable on the underside, from pale creamy to deep chocolate. 

 I did not know of its seasoned variation at the time, but I was 

 in Natal just at the change of season from wet to dry, when 

 the intermediate gradations were about, and I was struck with 

 the close resemblance of the sexes in pairs that I caught. I 

 am sorry to have nothing more definite to give on this head ; 

 it is a jioint much requiring exact and prolonged observation." 



Mr. Trimen furthermore entertains no doubt that much, if 

 not all, of the materinl upon which he based the conclusion 

 that the individuals of the same race tend to interbreed, 

 exists, distinctively labelled, in the South African Museum, 

 at Cape Town. It is greatly to be hoped that collectors will 

 in future cai'efuUy label all specimens captured in coifu, and 

 that the fact will be recorded on the labels in museums and 

 in private collections. It is tantalising to I'eflect upon the 

 number of interesting and important questions which could 

 be now decided if this practice had prevailed during the past 

 fifty years. The question of the possible origin of species 



* "More Letters," vol. i, p. 215, Letter 148. 



