( civ ) 
biologists tell us there is necessary a certain education of the 
hostile individuals. The creatures have to learn the meaning 
of the coloration; and this learning involves profiting by 
experience, . . . Here is as distinctly a mental process in¬ 
volved as any one might cite. . . . The action of natural 
selection, I may add for completeness, secures the survival of 
the insects so coloured, seeing that being warned, their 
enemies let them alone. The possibility of the evolution of 
the definite coloration turns, in fact, upon this series of 
psychological processes,” 
Here the psychic endowment of the enemy is seen to be a 
factor in the evolution of the prey; and it may of course be 
added that to ensure for the warning colour its full effect, it 
is necessary that its owner should possess the appropriate 
habits. Similar instances will at once occur to every field 
naturalist. Protectively-coloured insects instinctively seek 
corresponding surroundings. An interesting case of this is 
the fact which now seems fairly well established of yellow and 
white butterflies selecting for resting-places the neighbourhood 
of leaves or flowers of similar colour. Dr. Longstaff’s excel¬ 
lent plate, drawn from nature, of the resting habit of Eronia 
cleodora will occur to many of you. I ought to apologise for 
dwelling on so familiar a topic, but the fact really requires 
emphasising that the raw material of selection is neither 
purely physical nor purely psychical, but a complex of the 
two. The admission of this fact, so patent to evei’y observer 
of insects, has important consequences. For as soon as we 
can recognise a rudimentary form of mentality—the gaining 
of a definite result by the method of trial and error—we have 
a basis for habit, for memory, and eventually for the higher 
psychological faculties. In the instances that I have men¬ 
tioned of the correlation of appropriate habits with a pro¬ 
tective colouring, there is no reason to suppose the presence 
of anything like conscious accommodation; the actions in 
question are no doubt instinctive in the strictest sense. But 
quite low down in the animal scale, and even, I think it will 
be conceded, among the insects, we get indications of “ I’esidual 
pi'ocesses left by actual experiences ” leading to what can only 
be called memory. These processes, of undoubted utility, may 
