Allen and Jolivetle-—Light Reactions of Piloholus. 551 
age. In the second there is not only a large percentage outside 
the opening, but a considerable percentage outside of an area 
equaling’ in size the surface of the culture from which they 
started, showing that the accuracy of aim is appreciably dimin¬ 
ished with the distance from the opening. 
The Response of Pilobolus to the Stimulus of a Single 
Ooloeed Light. 
Experiments were also made to test the accuracy of response 
of Piloholus to colored lights as compared with white light. 
In these preliminary experiments, the light was admitted 
through plates of colored glass, and no attempt was made to 
obtain monochromatic light. When examined with the spectro¬ 
scope, the blue glass used gave a mixed spectrum comprising all 
the violet, blue and green, together with a narrow band in the 
red. The yellow glass used transmitted only the red half of the 
spectrum, including red, orange, yellow and half of the green. 
The red glass let through only the red light. The apparatus 
and methods used were the same as for the experiments already 
described, except that a small plate of colored glass was placed 
inside the box against the opening, care being taken to exclude 
all light except that which came through the colored glass. 
