Mimetic Attraction. 329 
Miillerian, and an addition is thus supplied to the evidence 
already existing in favour of the distasteful qualities of 
this and other Pierine genera.* 
Conclusion. If we take a comprehensive survey of the 
whole butterfly facies of the neotropical region, we cannot 
fail to be struck with the numerous cases of mimetic assimi- 
lation which it presents. It would in fact almost seem 
that scarcely any conspicuous form is completely isolated. 
In a region where enemies to insect life are so numerous, 
and competition for existence is so keen, a buttertly can 
hardly afford to be conspicuous unless it is also distaste- 
ful; nor is the mere individual possession of these 
qualities in the majority of instances sufficient for safety. 
Any form that requires to establish a reputation for 
inedibility, must as it were seek allies ; and no sooner does 
it make a bid for survival as a nauseous species, than it 
becomes subject to the influence of mimetic attraction, 
and probably finds itself drawn into the vortex of one of 
the great Miillerian associations. 
It is no doubt true that the process of mimetic assimi- 
lation is subject to limitation by the operation of other 
forces. Thus it may be needful that the resemblance to 
a model, though close enough to deceive enemies, should 
not be so close as to interfere with due recognition 
between the sexes. We know little of the means by 
which insects recognise each other, but there are at least 
some grounds for thinking that they are assisted at times 
by external marks. This may afford one reason for the dif- 
ferent ways in which the sexes of the same species occasion- 
ally react to mimetic influences ; and it may possibly be 
the meaning of the retention of a portion of the original 
white ground-colour in the males of certain species of 
Dismorphia, It is also quite conceivable that the aspect 
of every species is to some extent controlled by its 
physiological constitution ;+ and this fact may tend to 
disturb the perfect operation of the process of mimetic 
change. 
But notwithstanding all limitations, it remains the 
fact that any inedible form, in the midst of competing 
* Vide Trans, Eat. Soc. Lond. 1894, pp. 297, 298; zbid., 1896, 
pp. 74, 76. 
+ Vide Presidential Address by Prof. Meldola, Proc. Ent. Soc 
Lond, 1896, pp. Ixxx. et seqq. 
TRANS. ENT. SOC. LOND. 1897—PparT UI. (SEPT.) 22 
