BKEEDING EXPERIMENTS UPON ACR^A ENCEDON. 391 



W. A. Lamborn's Breeding Experiments upon Acrcea encedon (Linn.), 

 in the Lagos District o£ West Africa, 1910-1912. By Edward 

 B. PouLTON, D.Sc, F.R.S., Pres.L.S. 



[Read 2nd April, 1914.] 



The typical form of Acrcea encedon is a tawny butterfly with a black, 

 white-barred tip to the fore wing. The pattern thus closely resembles that 

 of the type form of Davaida clirysippiis, Linn. A. encedon is polymorphic 

 in both sexes, and the following forms are referred to in the present 

 memoir : — 



Infuscata, Stand., " the tawny areas of the typical forms are replaced by 

 smoky brown" (p. 112^). This form is transitional in one direction into 

 dark-grey butterflies without any tawny tint, and in the other into dark 

 forms of encedon. 



Alcippina, Auriv. " The h.-w. has a white central suffusion of varying 

 extent" (p. 212), thus reproducing the pattern of the alcippus, Cram., form 

 of clirysippus and of transitional varieties between alcippus and clirysippus. 



Daira, Godm. & Salv., " the black of apical half of f.-w. and the white 

 subapical band are absent. In some cases the subapical band may be traced 

 as a slightly paler area on the ground-colour. All the black markings much 

 reduced" (p. 212). 



Commixta, Poulton t • This form is a combination of the two preceding, 

 having the central white patch on the hind wing of alcippina, and a fore 

 wing approaching that of daira in the tint of the subapical bar, which is tawny 

 like the ground-colour. The pattern thus resembles the albinus, Lanz, form 

 of clirysippus, but the mimetic relationship is not suggested because of the 

 rarity of the model and its restriction to the parts of Africa where dorippus 

 is abundant. 



Lycia, Fabr. " The ground-colour of both wings is white, the black 

 markings being as in the typical form'"' (p. 112). '^Examples of the lycia 

 form may have the ground-colour pale creamy yellow " (p. 213)^ and are 

 thus transitional towards the sganzini form. 



Sgamini, Boisd. " The tawny areas of the typical form are replaced by 

 a dusky yellowish colour " (p. 212). 



* This description and those of the other forms except commixta are quoted from 

 H. Eltringham's great work, " Monograph of the African Species of the Genus Acrcea,^ 

 Trans. Ent. Soc. Lond. 1912, pt. i. 



t Trans. Ent. Soc. Lond. 1913, p. 409. 



