184 FOEESTRY WORK 



LARCH. 



Moths. 



Coleophora LariceUa. — The larvae of this tiny moth 

 bore into the leaves and suck the sap, the leaves shrivel- 

 ling up in consequence. The wounds made offer lodging- 

 places for the spores of Peziza WiUkommii. 



Saw-Flies. 



Nematus Erichsonii {the Large Larch Saw-Fly). — Until 

 recent years this insect has been rare and has been over- 

 looked. The caterpillars do great damage to young 

 trees, often entirely defoHating them. They are nearly 

 an inch in length when fully fed, and are greyish-green 

 in colour on the back and yellowish beneath, with 

 brownish spiracles on the segments. 



Plant Lice. 



Chermes Laricio {the Larch Aphis). — This insect is well 

 known because of its woolly covering, which is to be seen 

 on the leaves and young bark of Larch in almost any 

 wood. It is armed with a sucker, which exceeds in length 

 the body of the insect, and through which it sucks the 

 sap from the needles and bark. It not only injures the 

 tree directly, but there is no doubt that the spores of the 

 disease Peziza WiUkommii find lodgment in the minute 

 wounds made in sucking the juices. The alternate 

 generation of this insect passes its hfe upon the Spruce, 

 where it forms a gaU similar to a cone. These galls 



