288 GARDEN FOES. 



leaves, and these give birth to larvie half an inch long and 

 yellowish or whitish in colour, and marked or spotted 

 with black on the back and sides. The larvce feed on the 

 under sides of the leaves. In some seasons this pest does 

 considerable, harm to willow j^lantations. 



Eemedies. — Sprajqng with Paris Green (No. 11) or a 

 Kerosene Emulsion (No. 16) in summer, is the only 

 method of eradicating this pest. 



Wood Wasp, or Sirex — Two species of Sirex do 

 damage to coniferous trees, such as larch, pine, etc. The 

 Giant Sirex (S. gigas) is a wasp-like insect, black, banded 

 with yellow, and with black thighs, yellow feet, and 

 brownish-yellow membraneous wings. The other species, 

 the Steel Blue or Common Sirex (S. juvenicus), is blue- 

 black in colour, and has reddish or bluish feet. Both lay 

 their eggs in the bark, and in due course whitish cylin- 

 drical maggots are hatched, which bore into the trunks of 

 the trees, and do great damage. 



Kemedies. — Clear away dead or diseased trees, so that 

 the females cannot find a ready means of depositing their 

 eggs. Fortunately, these pests are not numerous. 



A number of larvae of moths feed on the leaves of trees, 

 but their injuries, as a rule, are not very serious. 



