5 8o 
Insects and Flowers 
this there really seems to be no other explanation of flower shape and appear¬ 
ance having the same validity as that of adaptation to insect visitors. 
The most effective criticism of this explanation is one against its effective¬ 
ness in explaining color, and particularly color-pattern. It is based on the 
general consensus of belief among zoologists and entomologists concerning 
the poorness of insect vision. The general character of this vision, with an 
account of the eye structure, is explained on pp. 30-33 of this book. The 
fixed short focal distance, the incompleteness and lack of detail incident to a 
mosaic image, and the lack of accommodation (only partly provided for by 
the shifting of the peripheral pigment) to varying light intensity, which are 
admitted conditions of insect vision, make it seem difficult to account for the 
intricacy in pattern common to many flowers on a basis of adaptation to 
animal visitors of such poor seeing capacity as insects. 
Experimental evidence touching this criticism is singularly meager when 
one considers the importance of the subject. If insects can accurately dis¬ 
tinguish colors, and at some distance, and can perceive fine and intricate 
details of color-pattern at very short distance, then the explanation of floral 
structure and pattern or adaptation to insect visitors has solid foundation 
for even the amazingly large and varied results which it attempts to explain; 
if not, it is hard to understand how the explanation is valid (at least in any 
such all-sufficient degree as commonly held), despite its logical character 
(in the light of our knowledge of the nearly limitless capacity for modifica¬ 
tion of natural selection) and the abundant confirmatory evidence. 
Most of the experimental evidence so far offered is that included in Dar¬ 
win’s account (“ On the Fertilization of Flowers by Insects ”); in Lubbock’s 
account of his experiments on honey-bees, familiar because of its presentation 
in his readable book, “Ants, Bees, and Wasps”; and in Plateau’s account 
of his more recent but less familiarly known experiments with various insects, 
including bees. Both Lubbock and Plateau are investigators ingenious 
in device, keen in deduction, and of unquestioned scientific honesty. Yet 
their conclusions are in direct contradiction. Lubbock believes that bees 
recognize colors at a considerable distance, that they “prefer one color to 
another, and that blue is distinctly their favorite.” Plateau finds that neither 
the form nor the brilliant colors of flowers seem to have any important attrac¬ 
tive role, “as insects visit flowers whose colors and forms are masked by 
green leaves, as well as continue to visit flowers which have been almost 
totally denuded of the colored parts”; that insects show no preference or 
antipathy for different colors which flowers of different varieties of the same 
or of allied species may show; that flowers concealed by foliage are readily 
discovered and visited; that insects ordinarily pay no attention to flowers 
artificially made of colored paper or cloth whether these artifacts are provided 
or not with honey, while, on the contrary, flowers artificially made of living 
