128 THE FOREST TENT CATERPILLAR 



causes them to congregate below the band, where they are 

 easily reached and destroyed. The commonest material em- 

 ployed for this purpose seems to have been ordinary cotton 

 batting, tied around the trunk of the tree. This is cheap, and 

 answers the purpose very well. Various mechanical barriers 

 have also been employed with more or less success, such as 

 bands of hemp, tin, and tarred paper. In some cases corre- 

 spondents reported that tar or kerosene was poured upon the 

 cotton. The use of kerosene in this way is not to be com- 

 mended, because of the danger that it may kill young and 

 thin-barked trees by being absorbed through the outer bark 

 to the sapwood beneath. 



Another sort of these barriers is found in the various viscid 

 substances with which the trees have been banded. These prevent 

 the progress of the caterpillars either by killing them through 

 contact as they attempt to cross, or by smearing theic legs in 

 such a way that they turn around as. soon as they come upon 

 it. The materials of this sort that have been used most are 

 lard, cottolene, sticky fly-paper, printers' ink, tar, and " rau- 

 penleim," or caterpillar lime. In many places rancid lard or 

 cottolene was used in considerable quantities, being smeared 

 around the trunk of the tree in a band about six to ten inches 

 wide. While this substance does not penetrate through the 

 outer bark of large elm trees, it should be understood that 

 there is danger in its use upon young, smooth-barked trees, on 

 account of the probability that the oil will penetrate to the 

 sapwood. Printers' ink seems to answer very well, as does 

 the sticky fly-paper until it is injured by rains. The raupen- 

 leim, or German caterpillar lime, recommended in my first 

 bulletin on this insect, has been tried in several localities, and 

 has , given very satisfactory results. A material similar to 

 raupenleim is now offered by the Bowker Chemical Company, 

 Boston, Mass., under the name "Bodlime." It should be re- 

 moved from the tree after danger from insects is past. 



On the whole, cotton seems to be the most advisable material 

 to use for bgrnding the trees. It is not expensive ; every one can 

 get it; it can be applied to all sorts, and sizes of trees with 

 little trouble, and with no danger to the tree. In case the 



