ATTACKING THE LEAVES. 153 



whole rows of trees may sometimes be seen as bare of foliage 

 during the early days of July as they are in midwinter. In 

 such instances the trees are obliged to throw out new leaves ; 

 and this extra effort so exliausts their vigor as to interfere 

 seriously with their fruit-producing power the following 

 year. Although very abundant in a given locality one 

 season, these slugs may be very scarce the next, as tiiey are 

 liable to be destroyed in the interval by enemies and by 

 unfavorable climatic influences. 



Remedies. — Hellebore in powder, mixed with water in the 

 proportion of an ounce to two gallons, and applied to the 

 foliage with a syringe or a watering-pot, promptly destroys 

 this slug; and Paris-green, applied in the same manner, in 

 the proportion of a teaspoonful to the same quantity of water, 

 would doubtless serve a similar purpose. Fresh air-slaked 

 lime dusted on the foliage is said to be an efficient remedy. 

 It has been recommended to dust the foliage with sand, ashes, 

 and road dust, but these are unsatisfactory measures, and of 

 little value. A very minute Ichneumon fly is said to lay 

 its eggs within the eggs of this saw-fly, and from its tiny egg 

 a little maggot is hatched, which lives within the egg of the 

 saw-fly and consumes it. 



No. 76. — The Green Pear-tree Slug. 



Another species of saw-fly, as yet undetermined, also attacks 

 the leaves of the pear. The larvae appear from about the 

 first to the middle of June, and eat holes in the leaves or semi- 

 circular portions from the edge. They are about half an inch 

 in length, nearly cylindrical in form, tapering slightly towards 

 the hinder segments. The head is rather small, pale green 

 with a yellowish tinge, and has a dark-brown dot on each side ; 

 the jaws are tipped with brown. The body above is semi- 

 transparent, of a grass-green color faintly tinged with yellow, 

 the yellow most apparent on the posterior segments; there is 

 a line down the back of a slightly dee2)er shade of green, and 

 one along each side, close to the under surface, of a paler hue. 



