8 BULLETIN 899, U. S. DEPARTMENT OF AGRICULTURE. 
band is to be applied. In this procedure too much of the outer bark 
is often removed, or the inner layer is gouged in the operation, result- 
ing in slight injury to the bark. It is very necessary preparatory to 
applying the sticky bands to secure a smooth surface. If not, the 
material, which sticks securely to the paddle used for applying, picks^ 
up much of the loose bark and in shaping the bands these particles 
are left on the surface and later form bridges for the caterpillars 
to cross. It is essential to scrape such bark as white oak, ash, or old 
apple trees both for the purpose of securing the desired smooth sur- 
face and to save material which would otherwise be wasted by work- 
ing into the crevices. The sticky material is ordinarily applied by 
means of a paddle made of hard wood 2 to 2J inches wide and with 
edge beveled obliquely for the convenience of the operator. 
Fig. 2. — Truck containing 11 tons of gipsy-moth tree-banding material, part of 25 tons 
made by United States Bureau of Entomology between 1917 and 1919. 
No scraping of the bark is necessary in applying gipsy moth tree- 
banding material unless such bark is very loose and scaly, as on an 
old white oak or apple, it only being necessary to rub the loose bark 
off with the hand. 
The material is most economically and conveniently applied by 
means of a special gun (PI. I). This consists of a tin cylinder 3 
inches in diameter and 8 inches long, the lower end being closed 
except for a small opening over which the nozzle or molder is at- 
tached by means of solder. The gun is also provided with a re- 
movable plunger. After the material is put in it is forced through 
the nozzle by the plunger, which is manipulated by means of two 
handles. The handles work similarly to those of a pair of large 
shears (one being riveted stationary to the cylinder). The other 
