INSECTS. 319 



appear futile on badly affected trees. Young trees were 

 treated by painting over the affected parts with a mixture 

 of melted resin and fish oil, in equal parts, applied warm. 

 Sir Joseph Banks removed them with a stiff brush. Spir- 

 its of tar, turpentine, oil, and soft soap, have been recom- 

 mended. After scrapi-ng off the rough bark, wash the 

 tree with alkaline solution, apply the same to the main 

 roots after laying them bare of earth.* 



Phemplli§[as pyri, Mrioaoma pyri, {Mtch), or I*em- 

 phigua Americanusf, ( Walker), is the Apple-root Blight. 

 It produces a similar condition in the roots, and was also 

 called the American Blight in England. It is composed 

 of warty excrescences upon the roots, containing in their 

 crevices minute lice, having their bodies covered with a 

 white cottony subtance. Removal of the earth, and the 

 application of soapsuds, has been recommended as a prob- 

 able remedy for the injuries done by this insect.** 



Psylla Pyri. — Some Aphides have the power of leap- 

 ing, like the leaf-hoppers, but they differ from those, in- 

 sects in having very large transparent upper wings, which 

 cover the sides of the body like a steep roof The genus 

 embracing these insects, is called Psylla. One of the 

 species was observed by Dr. Harris, upon a pear tree. 

 They live by suction, and having gorged themselves, the 

 juice runs down on the bark, producing a blackish color ; 

 young trees suffered excessively. As Dr. Phumb, of 

 Salisbury, Conn., had observed them in 1833 on some im- 

 ported pear trees, of which he lost several hundred in a 



• Harris' Kept. p. all. 



• ♦ For ftirther particnlarg respecting these insects, consnlt Dr. Fihsh's Bept, 

 p. G, and Harris' Sept., p. 341. 



