Insects injurious to Elms. 181 



Web-worm nests can be removed with mops dipped in carbolic acid 

 solution or kerosene. 



714. The elm is liable to suffer from a beetle which makes its at- 

 tack upon the bark, in the interior and on the under side, aud with- 

 out showing much appearance externally. The tree will begin to 

 languish, apparently while in the full vigor of growth, and, when 

 cut down, the bark will in a little while loosen and fall off, disclosing 

 a multitude of burrows. 



110. Perfect Insect of the Scnli/tiiK destructor, of natural size above, and enlarged be- 

 lo\\ : together with the Larva and Pupa, of natural size aud enlarged; and the 

 Burrows, under the Bark, made by the Scolytus multistriatus. 



715. A remedy has been proposed by Dr. Eugene Robert, of 

 Paris, which consists in shaving off the outer bark down to the liber 

 or live bark, from the whole trunk, and on scarifying down to the wood 

 the smaller branches, by drawing a sharp, three-bladed hooking in- 

 strument (with the middle blade somewhat shorter than the others) 

 lengthwise along the surface. This is, of course, an expensive pro- 

 cess, and only to be practiced in city parks, and other places where 

 the elms are prized as shade trees. It should be done only after the 

 summer growth is ended, and before the sap starts in spring. The 

 disagreeable color which this process leaves, may be covered up with 

 a paint composed of coal tar and yellow ochre, to imitate the natu- 

 ral shade of color of the bark. It is not found necessary to burn 

 the bark that comes off, unless it contains the perfect insects, for 

 the 'larvae will die without further attention, and the eggs, if they 

 should hatch, would find nothing to feed on. 



71G. Insects injurious to tJie Hickories. Of these 97 species are 



