Directive Coloration in Animals. 201 
The pulvilli are situated between the claws. They are large and 
glandular, and by secreting a viscid adhesive material enable a bee 
to walk up a smooth surface like that of glass. We thus under- 
stand why a bee fails in its attempt to walk up a moistened or 
powdered glass surface. When a bee walks on wood the pulvilli 
are turned back, when on glass the claws are similarly made to 
change their position. 
DIRECTIVE COLORATION IN ANIMALS. 
BY J. E. TODD. 
UCH has been written by Wallace, Darwin and others concern- 
ing the protective effects of coloration in animals, and this 
adaptation perhaps accounts for most of the chromatic characteristics 
of animals. Darwin has also shown how many may be accounted 
for by sexual selection, and Wallace has referred many of those, still 
remaining unexplained, to the play of color-producing forces 
uncontrolled by natural selection. 
So far as the author is aware, however, there has been no distinct 
enunciation of the principle sketched in the following pages. The 
nearest approach to it is a remark of Darwin in regard to the rab- 
bit’s white tail—that it might serve as guide to the young in follow- 
ing the old ones to the burrow; and another—that the stripes of 
the zebra may be of use to stragglers in recognizing their fellows at 
a distance, (Vide Am. Nar., 1877.) 
Wallace approves the suggestion, and, from some notes of his 
recent Baltimore lectures, it may be inferred that he has carried the 
Principle further. But in their published writings both these emi- 
nent naturalists refer several distinct cases to other sources, which 
in the following pages will be claimed as examples of what, for want 
of a better name, we have styled directive coloration. And whether 
the views hereinafter to be advanced prove to be entirely novel 
Or not, they have, so far as here expressed, sprung entirely from the 
author’s own observation and study. He regrets that both have 
necessarily been so limited that he cannot multiply examples as 
freely as nature has supplied them. What is here offered is only a 
sketch of what might be wrought out by any one having time to 
carry out the work in its details. 
