35 
In many cases the “Biological Survey Cat Trap” may be used to 
good advantage (Figure 6) . It consists of a box about 30 inches long and 
12 inches square with a false floor or treadle that rests on a fulcrum (a 
small piece of wood nailed across the floor of the trap), a trigger wire 
connected by a loop to a screw-eye at one side of the treadle back of the 
fulcrum, carried to the top of the trap and passed through a second 
screw-eye, and a vertical sliding door that is supported, when the trap is 
set, by the free end of the trigger wire. The door slides in grooves. The 
Figure 6. Cat trap. 
weight of the cat (or other animal) on the treadle beyond the fulcrum 
depresses that part of the treadle and pulls back the trigger wire, allowing 
the door to fall. In the back of the trap an opening about 3 inches 
square is covered with a heavy wire netting and is provided with a tightly 
fitting door to permit examination of any captured animal and the intro- 
