210 Mr. S. A. Neave: some bionomic 
It is therefore fairly safe to say, even considering the 
comparatively small number of specimens measured, that 
there has been a marked increase in the size of this spot 
as we advance northward along the East Coast, and thence 
turn westward to the apparent limit of the area of dis- 
tribution of the species. In addition to this increase in 
area of the spot, which is common to both species, it is 
fairly evident from the above table that there is an increase 
of a peculiar kind, the spot becoming distinctly more 
circular in shape as we proceed westward. As will be 
seen from the table, the ratio of breadth to length is 
appreciably greater in both species west of the Lake than 
east of it. In A. albimaculata this progressive increase 
occurs as we come up from the south, as well as from 
east to west. 
Other points of superficial resemblance which both 
species share, are greater expanse of wings and much 
better development of submarginal spotting on the hind 
wing. As might be expected, the resemblance in the 2 ? 
is markedly closer than in the f ¢. The @ specimen of 
albimaculata from Toro, figured, shows this resemblance in 
an astonishing manner, and has the additional character- 
istic of the pale buff area at the base of the hind wing 
being somewhat diffused. This resemblance becomes all 
the more significant when we remember that A. psyttalea 
does not occur in South Africa, while it is a very dominant 
species in Uganda, and also occurs, but not so commonly, 
in British East Africa. I have not had an opportunity of 
comparing numbers of specimens of A. psyttalea from the 
east and west shores of the Lake, but it is undoubtedly 
very common, and occurs in the Wiggins collection from 
every locality except the more open plains. 
This clear influence that the presence of one species has 
had upon two other closely allied ones (all being highly 
distasteful), seems to be one of the most striking examples 
of Miillerian mimicry that it is possible to imagine. 
The specimens of A. psyttalea are themselves remarkably 
interesting, the species being apparently in rather an 
unstable condition. The majority of the specimens, 
especially from the more eastern localities, are of the form 
damoclides, Staud., but a number from the north-west of 
the Lake are typical A. psyttalea, Plotz, from the tropical 
Atlantic Coast. These specimens, which are accompanied 
by many intermediates, are distinguished from A. psyttalea 
