EXTERMINATING NOXIOUS INSECTS. 271 



this varnish will crack when the growing trees expand, let 

 more varnish be applied early every spring, and bark lice 

 will not touch a tree. Tobacco-water, soda-wash, and quas- 

 sia only prepare the bark for the occupancy of these depre- 

 dators, rendering the surface soft and tender. Two dimes' 

 worth of pitch and tallow will be of more value in exclud- 

 ing lice than a dollar's worth of soap or potash-water. 



Some pornologists have stated that they have employed 

 a decoction of tobacco, with excellent results, in the follow- 

 ing manner : Procure a few pounds of leaf-tobacco, and boil 

 it to an impalpable pulp, which is afterwards mingled with 

 cold soft-soap, and worked until the mass is of the consist- 

 ence of thick paint. The rough bark is then scraped off 

 the trees, after which a heavy coat of this daubing is ap- 

 plied both to bodies and large branches. This material is 

 excellent for the purpose intended, so long as only a thin 

 layer of it will remain on the tree ; yet two or three heavy 

 and protracted storms will wash nearly all of it 

 to the ground. But the liquid grafting-wax will 

 adhere for several years. The expense of prepar- 

 ing and applying it will not exceed the expense 

 of the tobacco and soap. 



The Oyster-shell Bark Louse. Figure 105 rep- 

 resents a small part of a branch covered with the 

 eggs of the Oyster-shell Bark Louse. The only 

 true remedy we repeat is to scrape them off 

 and coat the smooth bark with liquid grafting- 

 wax. Lice are wonderfully destructive to both 

 the growth and health of trees ; and the rapidity 

 with which they increase when unmolested is as- 

 tonishing. They are the color of the bark itself, 

 and in shape and size like a flax-seed. In fre- 

 quent cases they actually kill the branch they 



J J Oyster-shell 



settle upon ; and in young trees oiten kill them Bark Lice. 



