July, 1914.] 



THE APPLE MAGGOT. 



53 



Table 6. 

 Length of Life of Flies in Rearing Cages in 1913. 



In the large field cages used in 1910, 1911 and 1913, the period 

 was still shorter. To take an example, in 1913, in connection 

 with other experiments, flies were confined in two special cages, 

 each of which enclosed a dwarf apple tree. Each cage measured 

 6 feet 4 inches by 6 feet by 6 feet high, and was covered with 

 fine mesh screen wire. The floor of each cage was covered with 

 moist sand, over which was stretched sheeting securely fastened 

 to the bottom of the cage. A barrier of tanglefoot prevented 

 ingress of ants small enough to pass through the meshes of the 



