HABITS OF THE ADULT FLY 47 
of the simplest and the food passes through the body 
with the greatest facility. 
Do Flies Have a Color Preference? 
Galli-Valerio (1910) states that the French agri¬ 
cultural journals have published a statement that Fe, 
having observed that flies do not rest upon walls cov¬ 
ered with blue paper, blue-washed the walls of his milk 
stables and that the flies then disappeared, and asks 
the question whether a similar method could be used 
to keep flies out of houses. He himself conducted ex¬ 
periments with a box having glass walls, 35 X 35 X 35 
cm. in size, and pasted on the walls bits of paper all 
the same size but of different colors, and afterwards 
introduced a certain number of house flies. For sev¬ 
eral days, after turning the cage in different positions 
so as to avoid error from other causes, he counted the 
flies which were standing on the different colors. The 
results were as follows: 
Clear green. 18 
Rose . 17 
Clear yellow. 14 
Azure . 13 
Clear red. 10 
Dark gray. 9 
White . 9 
Dark red. 8 
Black . 7 
Pale gray. 5 
Dark yellow. 5 
Dark green. 5 
Red . 4 
Orange . 3 
Clear brown. 3 
Pale rose. 3 
Very clear green.... 2 
Blue. 1 
Pale violet. 1 
Dark brown. 1 
Lemon yellow. 1 
The observer noted that eighty-seven flies stood on 
the clear light colors, and fifty-two on the dark. Blue 
