production of resemblance in allied species of Butterflies, 423 
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 is possible to imagine.” 
Before we accept this we may ask, what evidence is 
there for assuming that these butterflies have differed 
in any marked manner from their ancestral types? what 
evidence clear and satisfactory, 7.e. by observations in the 
field, has been brought forward to support the view that 
these butterflies are “highly distasteful”? and what 
observations have been made in these regions on the 
tasting habits of young birds? If they have been suffici- 
ently vigorous to cause the enlargement of a spot by the 
diameter of a pin’s head, such should not be entirely 
unknown to entomologists resident or even travelling 
through those countries, more particularly when we 
remember that many insectivorous birds in South Africa 
nest twice in the year. But these questions are common 
to every case of Miillerian mimicry, which I do not wish 
to discuss generally in this paper. 
One objection may be raised to Mr. Neave’s views, and 
that is that these spots begin to increase in size in British 
East Africa, where he tells us the model A. psyttalea is not 
very abundant,* and it is difficult to understand how or 
why the two abundant butterflies, echeria and albimaculata, 
should take as their model one scarcer or not more 
common than themselves; one would rather suppose the 
reverse would be the case. 
I am inclined to the view that this is an analogous case 
to that of the Huplocas, and that a denser rainfall and 
hotter climate is the cause of the small spotted and more 
heavily marked races of these species of Amauwris. Un- 
fortunately we are not in possession of sufficient meteoro- 
logical data to enable us to come to a definite decision, 
and the difficulties are increased by the enormous areas 
inhabited by these butterflies; but speaking generally the 
country round the Victoria Nyanza, which is approximately 
3,300 ft. above the sea, is hot and humid, and on the 
west side in proximity to the great forests of the 
Congo. 
Such a climate might well produce the dark hind- 
* His actual words are ‘‘ A. psyttalea does not occur in 8. Africa, 
while it is a dominant species in Uganda, and also occurs, but not 
so commonly, in British East Africa.” 
