288 Report oF THE DEPARTMENT OF ENTOMOLOGY OF THR 
sides, as shown by Plate XLII. On the inside of the front and 
top a strip projects two inches, against which the adjustable side 
rests when in position. Plate XLII, a. Two light strips extend 
across the top to support the canvas. On two sides of the frame 
and outside of the canvas two stout strips are bolted on a con- 
venient distance from the ground to serve as handles used in 
carrying the fumigator, as in Plate XLIII. The fourth side is 
made of the same material as the frame, and fits snugly in place 
against the two-inch flange previously referred to. 
The frame is covered with any suitable gas-tight material. 
Kight-ounce duck. was used on the two fumigators tested. It 
was sewed together in such a way that the three sides were 
covered with one large sheet. In one case raw oil and white lead 
were used to make the canvas gas tight, and in the other shellac 
with one coat of oil and white lead. Any of the substances used 
in making gas-tight tents will answer the same purpose. As it 
is desirable to have the canvas dark in color, lamp black was 
mixed with the oil in both cases. Heavy, unbleached sheeting 
is cheaper than canvas, weighs less and being thinner and closely 
woven takes less material to make it gas tight. With ordinary 
care in handling there is little danger of tearing the covering, 
especially if it is made of material as strong as eight-ounce duck; 
but as a precaution a stout wire net may be tacked on the inside 
of the upper half of the frame, thus preventing the limbs of the 
trees from touching the canvas. 
A strip of canvas one and one-half feet wide is securely tacked 
to each side of the base of the frame. The strips lap at the cor- 
ners, so that when the fumigator is in place they lie flat on the 
ground and can be covered with dirt or sand bags, thus prevent- 
ing the escape of the gas. The strips can be hooked up out of 
the way when the fumigator is being carried from one tree to 
another. Plate XLIII. The movable side of the fumigator can 
be easily put in place or taken off. Four handles, shown at Plate 
XLV, are conveniently placed for use. The two-inch flange 
against which it rests is covered with a good quality of felt 
about one-fourth of an inch thick, glued on as well as tacked, to 
