FLYTRAPS AND THEIR OPERATION. 5 
ject 1 inch at the bottom to form legs (/). The cone (4) is cut from 
the screen and either sewed with fine wire or soldered where the 
edges meet at (Z). The apex of the cone is then cut off to give an 
aperture (J/) 1 inch in diameter. It is then inserted in the trap 
and closely tacked to the hoop around the base. 
The construction of a cone of any given height or diameter is 
quite simple if the following method be observed. It is best to cut 
a pattern from a large piece of heavy paper, cardboard, or tin. 
Figure 3 illustrates the method of laying out a cone of the proper 
dimensions for the above trap. An ordinary square is placed on 
the material from which the pattern is to be cut; a distance (22 
inches) equal to the height of the cone is laid off on one leg of the 
square at A, and a distance (9 inches) equal to one-half of the 
diameter of the base of the cone is laid off on the other leg at 2, 
Fic. 5.—Method of laying out a pattern for the construction of a cone. Cut out on curved 
line C to # and on dotted lines from A to C and A to HE. (Author's illustration.) 
and a line is drawn between the points A and &. With the distance 
between these points as a radius and with the point A as a center, 
the portion of a circle C D, is drawn. With a pair of dividers, the 
legs of which are set 1 inch apart, or with the square, lay off as many 
inches on the are C' D, starting at (, as there are inches around the 
base of the cone, which in this case is about 564 inches, reaching 
nearly to the point #. Then add one-half inch for the lapping of 
the edges of the cone, and one-half inch which is taken up when the 
cone is tacked in, thus making a total distance from C to #' of 574 
inches. Draw a line from A to ( and another from A to /, and cut 
out the pattern on these lines and on the are from (' to /, as shown 
in figure 3. The edges AC and AF are then brought together, lapped 
one-half inch and sewed with wire or soldered. After the aperture 
