Color and Pattern and their Uses 
599 
Now that we have got in some degree acquainted with the ways in which 
colors are actually produced among insects, we may come back to the ques¬ 
tion asked in the first paragraph of this chapter, namely, “What is the use 
to the insect of all this variety of color and pattern? 5 ’ We may attempt now 
to get some clue to the significance of the color phenomenon. So wide-spread 
and well developed are color and pattern among insects that the presump¬ 
tion is strong that the utility of color-pattern is large. 
The only hypothesis that gives to colors and markings a value in the life 
of insects at all comparable with the degree of specialization reached by 
these colors and markings and by the special structures developed to make 
them possible, is that already referred to as the theory of protective and 
aggressive resemblances, of warning and directive patterns, and of mimicry. 
These various uses of color-patterns are all concerned with the relation of 
the insect to its environment; they are means of protecting the insect from 
its enemies or of enabling it to capture its prey. They are uses obviously con¬ 
cerned with the “struggle for existence”; they are “shifts for a living.” 
For the sake of clearness in the discussion of these various uses-—a discussion 
which must by the limitations of space be most unsatisfactorily condensed— 
the uses will be rather arbitrarily classified into several categories which in 
Nature are not as sharply distinguished as the paragraph treatment of them 
might suggest. 
General protective resemblance.—The general harmonizing in color and 
pattern with the color scheme of the usual environment is a condition which 
every field student of insects recognizes as widely existing. The difficulty 
of distinguishing a resting moth from the bark on which it is resting, a green 
caterpillar or leaf-hopper or meadow grasshopper from the leaf to which it 
clings, a roadside locust or bug from the soil on which it alights, is a diffi¬ 
culty which has to be reckoned with by every collector. Now while there 
are few human collectors of insects, there are hosts of bird and toad and lizard 
insect-hunters, to say nothing of the many kinds of predaceous insects them¬ 
selves who use their own cousins for chief food. So that where this diffi¬ 
culty of distinguishing the resting insect from its environment is sufficient 
to postpone success on the part of the insect-hunting bird or lizard, the life 
of the protectively-colored insect is obviously saved, for the time, by its dress. 
This is a utility of color and pattern than which there can be, from the insect 
point of view, nothing higher. 
Variable protective resemblance. —While with most insects all the indi¬ 
viduals of one species show a similar color and pattern, it is noticeable that 
with a few species there is a marked variability or difference in color and 
sometimes in markings. Locusts of various species of the genus Trimero- 
tropis show a variability in color of individuals ranging through gray, brown, 
reddish, plumbeous, and bluish, and such accompanying variab'lity in mark- 
