198 Practical Forestry 



considerable damage to osier plantations, and would appear 

 to be greatly on the increase of late years. Much damage 

 has been done to osier holts in various parts of the country, 

 and in northern Ireland the ravages of this beetle were 

 particularly noticeable during the past five years. The 

 insect, which is metallic green or blue in colour, passes the 

 winter in the adult state, at which time it may be found 

 amongst refuse of the osier beds, such as the heaps of bark, 

 and also at the base of old stools and beneath stones or other 

 shelter. The larvae have a tough yellowish cuticle with 

 conspicuous brown bristles, the head and prothorax being 

 black and hard. The eggs are ]aid on the undersides of the 

 leaves in spring, and when the larvae are hatched they feed 

 on the leaves, eating holes quite through to the upper sur- 

 face. Burning all rubbish in the osier beds is to be recom- 

 mended, and spraying with Paris green or lead arsenate has 

 been found useful. 



The Larch Sawfly (Nematus Erichsonii). This is a 

 species of sawfly the larvae of which bear considerable 

 resemblance to those of the caterpillar of the pine sawfly, 

 and also to that of the better known gooseberry caterpillar. 

 The larvae are about three-quarters of an inch long, and 

 possess twenty feet. From July to August they feed on the 

 leaves of the larch, and a plantation that has been attacked 

 presents a partially leafless condition with quantities of 

 the brown cylindrical cocoon cases lying amongst the grass 

 beneath the trees. There have been several notable in- 

 stances in which larch plantations have suffered severely 

 from the attacks of this insect, and in northern England, 

 particularly Cumberland, whole areas of plantation have 

 been attacked. Burning all brushwood and grass beneath 

 the trees in infected plantations is probably the best means 

 of lessening the numbers of this dread insect in our larch 

 plantations. 



The Spruce Gall Aphis (Chermes abietis). This is a 

 common insect, and one that renders many fine young spruce 

 trees very unsightly by reason of the cone-like excrescences 

 that are formed by the action of the insect on the shoots of 

 the infested specimen. The formation of this excrescence 



