The Elm-bark Beetle. 37 



relaxed in some other way, when probably the 

 scale will depart. 



The Elm-bark Beetle, in its attack, is some- 

 what similar to the Ash-bark Beetle already 

 described. It is no doubt in its effect well- 

 known to all frequenters of woods and timber 

 yards. The borings take place between the 

 soft inner bark and the alburnum. Their 

 presence may be detected in June by the 

 wood-dust caused by the boring of the insect 

 when seeking entrance for the laying of its 

 eggs ; these eggs, from about a hundred 

 in number, are laid along the side of the 

 burrow. The young grubs work at right 

 angles to the original burrow, the burrow 

 growing larger as the grub proceeds, on 

 account of its increased size. At the end 

 it becomes a pupa, and when fully developed 

 pierces its way through and leaves the tree, 

 this usually taking place in the month of 

 August. In this case again is evidence of 

 the necessity of health to resist attack, for it 

 is chiefly confined to trees in an impaired 

 state of health. 



The prevention of this lies mainly in the 



