i) 
— 
ADAPTIVE COLORATION 2 
the senses of the lower animals are co-extensive in range 
with our own. As a matter of fact, birds detect insects with 
a facility far superior to that of man, and destroy them by 
the wholesale, in spite of protective coloration. Thus, as 
Judd has ascertained, no less than three hundred species of 
birds feed upon protectively colored grasshoppers, which they 
destroy in immense numbers, and more than twenty species 
prey upon the twig-like geometrid larvee; while the weevils 
that look like particles of soil, and the green-striped caterpillars 
that assimilate with the surrounding foliage are constantly to 
be found in the stomachs of birds. 
After all, however, protective resemblance may be regarded 
as advantageous upon the whole, even if it is ineffectual in 
thousands of instances. An adaptation may be successful 
even if it does fall short of perfection; and it should be borne 
in mind that the evolution of protective resemblances among 
insects has probably been accompanied on the part of birds by 
an increasing ability to discriminate these insects from their 
surroundings. 
Warning Coloration.—In strong contrast to the protec- 
tively colored species, there are many insects which are so 
vividly colored as to be extremely conspicuous amid their nat- 
ural surroundings. Such are many Hemiptera (Lygeus, 
Murgantia), Coleoptera (Necrophorus, Lampyridze, Coccinel- 
lide, Chrysomelide), Hymenoptera (Mutillidee, Vespidee), 
and numerous caterpillars and butterflies. Conspicuous col- 
associated with 
ors, being frequently—though not always 
qualities that render their possessors unpalatable or offensive 
to birds or other enemies, are advantageous if, by insuring 
ready recognition, they exempt their owners from attack. 
Efficiency of Warning Colors.—Owing to much disagree- 
ment as to the actual value of “ warning ”’ colors, several in- 
vestigators have made many observations and experiments 
upon the subject. Tests made by offering various conspicu- 
ous insects to birds, lizards, frogs, monkeys and other insec- 
tivorous animals have given diverse results, according to cir- 
