( Ivii ) 
in colour and form to the objects among which they lived ; 
it prompted further observation and experiment because more 
evidence was required as to the protected character of the 
insects which were copied ; it raised the whole question of the 
existence of such protected species in nature, and the 
question has been answered so far in the affirmative, although 
there is still a large field for further experimental observation 
waiting to be explored. The facts have increased enormously 
since 1861, the search for new instances having been stimu- 
lated by the explanation suggested by Bates, and the syste- 
matist is now no longer in danger of being deceived by 
superficial resemblances. 
The theory of Bates left unexplained the resemblance 
between species belonging to protected groups to which he 
had himself called attention in his original paper ; an exten- 
sion was required and was made by our Hon. Fellow, Fritz 
Midler in 1879, and as a result, whether this extension be 
considered valid or not — a point which I am not now 
raising- the systematist is now more fully alive to the 
superposition of external similarity upon structural resem- 
blance due to true blood-relationship, as- can be seen from the 
writings of Moore on the genus Euplcea, and of Wood- 
Mason and others on certain Papilionidse. As another result 
of Fritz Miiller's hypothesis, the question of inherited 
knowledge of edible and inedible species on the part of insect- 
eating creatures has likewise been raised, and has already 
led in the hands of Professor Lloyd Morgan to some inter- 
esting experimental conclusions. 
As the product of a theory we thus have a large body of 
real and tangible knowledge gleaned from Nature ! Mere 
casual observation would never have revealed the widespread 
existence of the phenomenon if the stimulus to look out for 
it had not come from the theoretical side. 
It is not the bare record of the comparatively few cases of 
mimicry that constitutes the highest value of these classical 
memoirs — it is the speculation, the hypothesis, the suggested 
cause of the phenomenon that has given vitality to what 
would otherwise have been a disconnected and meaningless 
set of facts. But the consequences of the introduction of 
