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XV. Pseudacrasa poggei and Limnas chrysippus; the 

 numerical proportion of mimic to model. By 

 Horace A. Byatt, B.A., F.E.S. With a note by 

 Professor E. B. Poulton, D.Sc, M.A., F.R.S., etc. 



[Read April 5th, 1905.] 



Plate XIV. 



These butterflies were found among a collection of some 

 1200 specimens given to me by Pere Guilleme of the 

 White Fathers' Mission to Central Africa, under whose 

 direction they were collected at his station at Kayambi, 

 in Awemba country, N.E. Rhodesia, near the sources of 

 the Congo, locally called the Chambezi, between October 

 1898 and January 1899. 



His system was to send out a number of native school- 

 boys — his " gamins," as he called them — each armed with 

 a net and a book, and orders to capture anything and 

 everything that came in their way, placing their captures 

 between the leaves of the book for safe carrying home. 



He particularly mentions that he told his boys to take 

 " des specimens aussi varies que possible ; " and that they 

 would do this literally I know from my own experience of 

 natives, for I have found them generally unable to dis- 

 criminate between species, and when sent out by me on 

 similar occasions they have returned with large numbers 

 of the insect most in evidence at the moment, and a pro- 

 portionally smaller number of others. It is, therefore, 

 allowable to suppose that the whole lot which came into 

 my possession gives a very fair idea indeed of the numerical 

 strength of the several species found in the locality. 



On opening the papers and examining the specimens — 

 which have suffered a good deal from the damp and 

 neglect of seven years — it was found that roughly ODe- 

 third of the whole collection consisted of Limnas chrysippus, 

 L., and its mimics; and among these latter were seventeen 

 specimens of Pseudacrsea poggei, Dewitz, — many of them 

 in a fair state of preservation, though, with the rest, they 

 show signs of being unduly pressed between the pages of 

 the book, and are somewhat dulled in colour by damp. 



TRANS. ENT. SOC. LOND. 1005. — PART II. (.JULY) 



