84 MIMICRY IN EAST AFRICAN BUTTERFLIES 
local conditions, or as he calls it 4 External Causes,’ is entirely 
inadequate to explain the vast array of interesting observations 
which he records, but it is, perhaps, permissible to quote one 
pregnant sentence : — ‘ There is something attractive and 
plausible in the idea that the strong mutual resemblances 
within a group of butterflies of different genera and sub- 
families, inhabiting a single locality, are due to the direct action 
of peculiar local or chemical influences ; but the suggestion 
loses all its attractiveness when it is applied to the resemblance 
between a spider and an ant, or a moth and a wasp.’ That 
such cases do occur there can be no manner of doubt. Even 
in England it is well known that there are moths, such as the 
hornet clearwing, which are deceptively like stinging Hymen- 
optera, and Professor Poulton has himself figured examples of 
spiders which bear an extraordinary resemblance to abundant 
and well-protected ants. 
This last is a very remarkable case on account of the pro- 
found modifications which are needed in order to produce the 
resemblance. A spider has eight legs and no antennae, and in 
these particular instances two of the legs are held up in such a 
position as to give the appearance of the antennae of the ant. 
To come now to the more particular subject of the present 
paper, Mimicry in East African Butterflies. There are certain 
phenomena, which are indeed common to mimicry all the 
world over, which are a great help to its study. The models 
are not distributed indiscriminately in all the families of butter- 
flies but are characteristic of certain genera and even families. 
The Danaidae and Acraeinae are the models for mimicry every- 
where. And although the latter subfamily is peculiarly 
characteristic of Africa the Daniadae which are comparatively 
few are far more extensively mimicked. 
The most abundant and widely distributed of these is 
Limnas chrysi'p'pus. This species has been proved by actual 
experience to be excessively distasteful to many of the enemies 
of insects. It occurs under three forms, the most usual being 
a brown butterfly of considerable size with a broad black tip 
marked with a row of rather large white spots near its junction 
with the ground colour. The form prevalent in West Africa 
