THE WAY OF THE WILD 77 
lights as would any other species, but stands with the hinder 
points of its wings close to the stem, the other portion standing 
out like a dead leaf not yet fallen. The peculiar long-drawn- 
out point at the rear of the wing, from its close resemblance to 
the stem of the leaf, heightens the deception (see Fig. 11). 
Instances could be multiplied indefinitely showing how one 
form in nature imitates or more properly resembles another, 
generally to the advantage of one or the other, if not of both. 
For example, certain flies without stings closely resemble bumble- 
bees, not only in general appearance but also in manner of flight. 
The resemblance might be closer, but it no doubt is some ad- 
vantage to the impostor and insures him a wider berth from 
boys, at least until they learn the imposition, after which its 
advantage is a matter of doubt, as any boy can testify who has 
had the satisfaction of tormenting ‘‘ shade bumblebees.” 
Design in nature. The consistent student must not interpret 
these and similar facts too literally. The hasty observer and 
careless writer sees ‘“‘ design” in every detail. The fact is that 
in nature there are many resemblances of structure between 
widely separated species, and it is inevitable that similarities 
should occur. When once they happen to be of selective value, 
then natural selection rapidly shapes them up and makes the 
resemblance closer still. 
For example, the flat, thin structure of the leaf requires some 
system of ribs and veins for its support. The wing of the 
butterfly has the same structural necessity and for the same 
mechanical reason. The two structures, therefore, the one plant 
and the other animal, are built and must be built upon a similar 
plan. It is inevitable, therefore, that there should be many close 
structural resemblances, and as the butterfly takes his initial 
color from the green of the leaf, these resemblances are often 
still further heightened by remarkable color effects. In many 
ways, therefore, butterflies resemble foliage. 
Causes of color in animals and plants. The world owes no 
little of its beauty to the range and variety of color of its plants 
