(2 rp) [xlvi, xlvii 
must confess that I find it harder to believe all this than that 
birds either do or once did exercise a powerful selective 
influence over butterflies. The question of snakes is next con- 
sidered. In Brazil, we are told that eight species of harmless 
snakes mimic the same number of species of Hiaps. Then, as 
if to counterbalance this unfortunate evidence, it is pointed 
out that three harmless genera mimic the poisonous genera and 
the latter prey on the former, so that they are not protected 
except from birds. But surely whilst being protected from 
birds and mammals, they are protected from their poisonous 
enemies by their resemblance to them, unless the poisonous 
ones prey on each other. The case is a complicated one, and 
appears to exhibit protective and aggressive resemblance 
respectively in the two genera, but brought about by the same 
means. The balance of nature has been reduced toa fine point. 
In the next section the author cites a case in whicha brown 
Euplea, a Danais, and a Hypolimnas, all much alike, are 
observed to fly together. Mr. G. F. Mathew maintains that. 
all these three genera are avoided by birds, and the case is 
given as one to which the Miillerian theory is therefore inap- 
plicable. I cannot help thinking, however, that the case is one 
to which the Miillerian theory precisely applies, and the para- 
graph only goes to confirm Professor Meldola’s contention 
that Professor Packard did not understand the Miillerian 
hypothesis at all. 
The remainder of the paper is devoted to an able and inter- 
esting discussion on the origin of the markings of mammals, 
the effect of the blending of colours when the animals are in 
motion, and other matters. Deeply interesting as this portion 
is, it hardly bears on the case of butterfly mimicry. Animals 
which develop their external attributes of colour and markings 
under the life-long influence of light and shade, colours which 
are for the most part cryptic, though presumably developed by 
natural selection, cannot be compared to creatures which reach 
full colour and pattern development in an hour or so after 
emerging from the pupa, and which moreover can produce 
such diverse forms, as for instance the male and female 
Hypolimnas misippus, from the same batch of larve fed and 
pupated under the same physical conditions. 
