suggestions as to insect colours and patterns. 573 
he knows in the living state, and of the skunk, he cannot 
contend, I think, that his criticisms are powerful enough to 
transfer these examples into the bionomic group which con- 
tains the well-known examples of cryptic colouring—the 
skunk into the same category as the hare or ptarmigan, the 
under-side colouring of the Danaine butterflies, or the Nym- 
phaline genus Limenitis (Basilarchia) into the same category 
with that of Grapta or Kallima, etc. I believe the whole 
of his criticism of warning colours can be accepted, and 
can be reconciled with the existing hypotheses. All 
animals with warning colours have enemies, all are 
liable to special attacks, in times of exceptional hunger, 
by enemies which would at other times neglect them. 
Even the skunk has special bird enemies. Provided such 
forms are easily seen and avoided by enemies which 
respect their special modes of defence, it is clearly an 
advantage to be as far as possible concealed from those 
which do not respect them. Hence conspicuousness, but, 
as Mr. Thayer tells us, something very far short of ideal 
conspicuousness. The black and white pattern of the 
skunk is probably glaring and conspicuous enough to all 
enemies near at hand, but at the immense distance covered 
by the long-range sight of a predaceous bird it may melt 
into an inconspicuous grey. 
The same kind of interpretation probably holds for a 
cryptic element whenever it exists in the appearance of 
butterflies belonging to distasteful sub-families. It is the 
probable meaning of the transparency so widespread in 
the Lthomiinex, although I do not think it is so effective 
in concealing as Mr, Thayer supposes. We must remember 
that many of these transparent species are excessively 
abundant, flying in clouds often made up of the individuals 
of several species and different genera. I quite recognize 
that the transparency may protect such forms against 
distant enemies, but I should be much surprised if the 
species of Methona and Thyridia, as well as Dismorphia 
orise, of which they are the models, are not rendered 
extremely conspicuous to enemies close at hand, by their 
numbers, habits of flight, and attitudes of rest. As Mr. 
Thayer has said, the black and white markings will melt 
into an elusive grey on a rapidly vibrating wing ; but the 
specially protected groups have developed a sailing flight 
which shows off the elements of pattern to perfection. 
When the body in such groups is effacively graded the 
