( 36 ) 

 Wednesday, December 6th, 1911. 



[lxxxix 



( !( 'NTKASTS IN COLOURING BETWEEN CERTAIN SPECIES OF BUT- 

 TERFLIES from the Lagos District ani> their Geographical 

 Races at Entebbe. — Prof. Poulton exhibited ;i series of 

 specimens bearing upon the view, again recently advanced, 

 that changes of colour and pattern in allied forms are due to 

 climate, and especially to moisture. The western specimens 

 were all collected or bred by Mr. \V. A. Lamborn, just above 

 sea-level, in the Lagos district. The Uganda specimens were 

 xc] 



collected by Mr. 0. A. Wiggins, at about 4000 ft., in the 

 neighbourhood of Entebbe. The average rainfall at Epe, near 

 Mr. Lamborn'e locality. Oni, 70 miles east of Lagos, is about 

 equal to thai of Entebbe, being 60'5 inches to 59*1. The first 

 example was Plant a epaea, Cram., and its Uganda sub-species 

 epaea paragea, Grose-Smith. In the Latter the fuscous ground- 

 colour had been greatly increased, while correspondingly 

 reduced pale-yellowish markings represented the conspicuous 

 fulvous of the west< rn male and white of the western female. 

 Tims the sexual dimorphism of pattern, marked in the west, 

 is losl in the far duller Uganda race. Together with these 

 exhibited the males and females of Papilio oynorta, P., 

 from thr same localities. While the males showed no appre- 

 ciable change, the western female was a beautiful mimic of 

 the female epaea and the more eastern female (peculiaris, 

 ii equally beautiful mimic of the dingy-looking 

 paragea. In this latter case a climatic cause could hardly lie 

 invoked, for it is unreasonable to suppose thai the male and 

 female larvae and pupae are exposed to different conditions 

 or that they differ in their sensitiveness to climatic influ- 

 i nee. It may well be argued, however, that we Bhould not 



expert a Papilionine and an .\ei aeine to exhil.it the same 

 kind of BUSCeptibility. But even the investigation of other 

 Planemas [Aeraeinai ) at Entebbe does not support the con- 

 clusion that the pattern of /xiragea is a climatic effect. Thus 

 it is seen in the exhibited specimens that the rich fulvous 

 and black P. consanguinea, Auriv., from the Lagos district 



