96 THE FOREST TENT CATERPILLAR 



that the caterpillars are soon able to cross over it. Sticky fly- 

 paper ;t Tanglefoot" has been commonly* used with a large 

 degree of success ; it is effective, cheap, and easily applied. 

 Rather wide bands of it are necessary to prevent bridging over 

 by the dead or dying caterpillars. The chief difficulty with 

 this paper^is its liability to injury by rain, the wetness causing 

 it to tear so readily that it may not last long. In some cases 

 bands of greased tin have been successfully employed. 



A better substance than any of these, however, is Raupen- 

 leim or "Caterpillar-lime," a material manufactured in Ger- 

 many for application to the bark of trees to prevent the ascent 

 of caterpillars and other crawling insects. It is to be put on as 

 a rather wide band, or as two narrower bands. In the case of 

 large trees with thick bark the material may be smeared 

 directly upon the bark, while in the case of young trees and 

 those with smooth bark it is safer to apply the Raupenleim by 

 smearing it upon a band of heavy wrapping paper or some 

 other thick and firm paper tacked upon the tree. Any loose 

 bark may be scraped off the portion of the trunk which is to 

 be covered by the paper before the latter is put on ; and it is 

 sometimes worth while to insert a thin layer of cotton waste, 

 or some similar material, beneath the paper to fill up crevices 

 and thus prevent any insect from crawling through beneath the 

 paper. Then the Raupenleim may be smeared upon the 

 paper the thickness of about a quarter of an inch, and left as 

 long as it remains sufficiently sticky to entrap any insect that 

 attempts to crawl over it. As it will remain eight or ten 

 weeks in a sticky condition, a single application early in the 

 season will probably last until danger from the caterpillars is 

 past. 



It should be distinctly understood that there may be danger 

 of injuring trees with smooth and thin bark if this Raupenleim 

 is smeared directly upon the bark. For young trees and those 

 older which have a smooth bark I recommend that the Rau- 

 penleim be applied by placing it upon strips of thick paper 

 tacked to the trunks of the trees. Even in the case of bearing 

 apple trees this would probably be the safer method, and it 

 should always be adopted for peach trees, if not for pear trees 

 also. After the Raupenleim has been on some weeks the sur- 



