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 Dark green 5 



Rose 17 Red 4 



Clear yellow 14 Orange 3 



Azure 13 Clear brown 3 



Clear red 10 Pale rose 3 



Dark gray 9 Very clear green. ... 2 



White 9 Blue i 



Dark red 8 Pale violet i 



Black 7 Dark brown i 



Pale gray 5 Lemon yellow I 



Dark yellow 5 



The observer noted that eighty-seven flies stood on 

 the clear light colors, and fifty-two on the dark. Blue 



