Mechanical Destruction of Insects 145 
the batting can be turned over and down like an inverted 
tunnel, which forms the bar to the ascending caterpillars. 
The caterpillars collect below the band and should, from 
time to time, be gathered and killed. A band of tarred 
paper may be substituted for the cotton, or else light burlap 
(eight ounce, eight to ten inches wide). These devices 
are not very sightly; a neat metal protector, consisting of a 
brass band with teeth like a comb, tacked to the tree, is an 
improvement upon them, as regards appearance. Where 
the bark is rough, it may become necessary to smooth it, 
so that the band makes a tight joint. Where a large num- 
ber of trees are to be protected, as in streets and parks, it 
will be found cheaper to use a band made of a sticky sub- 
stance. For this purpose theré are several preparations 
made from crude petroleum; a German one sold under the 
name ‘‘Raupenleim” + was the original one, an American 
one called ‘“ Dendrolene,” * and another, “Tree-Tanglefoot,” 
all more or less greasy, smooth, and of butter-like consist- 
ency. The last mentioned remains effective a longer time, 
because it does not dry, but it is apt to injure the bark of 
young trees, hence in such cases it should be applied with a 
protective paper band underneath. 
These applications are made, after having smoothed the 
bark, three to six inches wide and a quarter of an inch thick. 
There are devices for handling these substances expeditiously, 
but ordinarily a trowel may be used. The bands should be 
placed at sufficient height to avoid disagreeable accidents 
from contact with passers-by. Should the band become dry, 
it will have to be renewed. 
These coatings can also be used to advantage to keep 
1To be obtained from Bowker Fertilizer Co., Boston, Wm. Mengel 
Son, New York. 
2'To be obtained from Prof. F. L. Nason, New Brunswick, N. J. 
