notes on Butterflies from the Victoria Nyanza. 211 
damoclides by a reduced pale area at the base of, and the 
absence of submarginal spots on the hind wing, giving 
them a marked general resemblance to western forms 
such as A. damocles, Beauy. (non Fabr.), and hecate, Butler. 
A. hecate does itself occur sparingly on the shores of the 
Lake ; as also another species allied to it, viz, the recently- 
described A. disa, mihi (2).* In this species all the white 
markings and (especially the pale area at the base of the 
hind wings) are even more reduced than in hecate. 
The above is a striking case of a species acting as a 
model, at one and the same time as certain individuals of 
it are being attracted into another group. This compli- 
cated condition of mimetic association in which a species 
is both model and mimic at the same time is well known 
to be paralleled in the Neotropical region, where we find 
similar but still more complicated instances among the 
Danaine, Heliconine and Ithomiine. 
The specimens of Amauris niavius, Linn., are also deeply 
interesting. Whilst the specimens taken west and north- 
west of the Lake (with one exception from Entebbe which 
is intermediate in character) are all A. niavius niavius, 
the typical western forms, those from the north-eastern 
shores numbering about thirty specimens are nearly fifty 
per cent. of them intermediate to A. niavius dominicanus, 
which occurs at Mombasa. 
The two chief points of distinction in the latter form 
are the greater extent of all the white areas and spots on 
both wings. The spot within the cell and subapical bar 
of the fore wing, together with the white basal area of the 
hind wing, are especially larger. In A. wiavius niavius 
the discocellular spot is evanescent, and the white basal 
area of the hind wing seldom even reaches the extremity 
of the cell. 
The specimens above mentioned occurring from the 
east of the Lake are remarkably intermediate in respect 
of these characters. The discocellular spot is well marked 
but not so large as in dominicanus. The subapical white 
bar is broader than in niavius, but not so broad as in 
dominicanus. The basal white area of the hind wing 
extends well beyond the extremity of the cell, but not 
nearly so far as it does in dominicanus, 
The two instances above of two geographical forms of a 
species meeting and appearing in an intermediate form on 
* Loc. cit. p. 324. 
