HEMIPTERA. 195 



has existed for some time, and extended its influence over the 

 parts of a large tree, it will take its course, and the tree will die. 

 He says that he has removed this blight from young trees, and 

 from recently attacked places in those more advanced, by painting 

 over every node or infected part of the tree with a composition con- 

 sisting of three ounces of melted resin mixed with the same quan- 

 tity of fish oil, which is to be put on while warm, with a painter's 

 brush. Sir Joseph Banks succeeded in extirpating the insects 

 from his own trees by removing all the old and rugged bark, and 

 scrubbing the trunk and branches with a hard brush. The appli- 

 cation of the spirits of tar, of spirits of turpentine, of oil, urine, 

 and of soft soap, has been recommended. Mr. Buel found that 

 oil sufficed to drive the insects from the trunks and branches, but 

 that it could not be applied to the roots, where he stated numbers 

 of the insects harbored. The following treatment I am inclined 

 to think will prove as successful as any which has heretofore been 

 recommended. Scrape ofT all the rough bark of the infected 

 trees, and make them perfectly clean and smooth early in the 

 spring ; then rub the trunk and limbs with a stiff brush wet with a 

 solution of potash as hereafter recommended for the destruction 

 of bark-lice ; after which remove the sods and earth around the 

 bottom of the trunk, and with the scraper, brush, and alkaline 

 liquor cleanse that part as far as the roots can conveniently be un- 

 covered. The earth and sods should immediately be carried 

 away, fresh loam should be placed around the roots, and all cracks 

 and wounds should be filled with grafting cement or clay mortar. 

 Small limbs and extremities of branches, if infected, and beyond 

 reach of the applications, should be cut off and burned. 



There are several other species of Eriosoma or downy lice in 

 this State, inhabiting various forest and ornamental trees, some of 

 which may also have been introduced from abroad. The descrip- 

 tions of foreign plant-lice are mostly so brief and imperfect, that it 

 is impossible to ascertain from them which of our species are 

 identical with those of Europe ; I shall therefore omit any further 

 account of these insects, and close this part of the subject with a 

 few remarks on the remedies to be employed for their destruction 

 generally, and some notice of the natural enemies of plant-lice. 



Solutions of soap, or a mixture of soap-suds and tobacco water, 



