LIPARIS MONACHA. 315 



October, 1862, 31,360,000 cub. feet of wood were killed, 

 30,823,000 cub. feet by the Nun, and 437,000 cub. feet 

 by bark-beetles. The ravaged area exceeded 21,000 acres, and 

 in East Prussia, between 1853 and 1863, over 467,000,000 cub. 

 feet of wood had to be felled, while 267,000 acres were 

 devastated. 



The damage done in the neighbouring Russian province was 

 still greater, and it has been computed that by the Nun and 

 bark-beetles 6,400 geographical sq. miles of forest in Russia, 

 and in Prussia 600 sq. miles, altogether 7,000 sq. miles of 

 forest, were destroyed, and at least 6,427,500,000 cub. feet of 

 timber killed. It was noted as a curiosity that the manuring 

 of the forest soil by. the dung of the caterpillars, and the 

 opening-out of the woods, produced such 

 a heavy growth of grass that the stags, 

 owing to the greater abundance of 

 provender, bore antlers of unusual size. 



In 1889 and 1890 this insect proved ^ ] 

 very destructive in Bavaria, south of l||| 

 the Danube, the expenses of the cam- !f| 

 paign against it amounting to as much 

 as 100,000. K * 16 i" - Bir f ch 



eaten by the caterpillar 



In attacking broadleaved trees, the O f L. momeha, L. 

 caterpillars frequently eat the base of 

 the leaves, letting the remaining portion fall to the ground : 

 this is the case with birch and aspen, whilst with beech and 

 oak only a portion of the leaf is eaten, the leaf -stalk being 

 usually untouched (Fig. 160). 



The attack is never fatal to broadleaved trees. 



d. Protective Rules. 



i. Avoidance of pure spruce or Scots pine woods and introduc- 

 tion of suitable species, especially beech, in intermixture with 

 such woods. 



ii. Thinning. By careful thinning future remedial measures 

 are facilitated, and a better control over the collectors of eggs, 

 larvae or pupae is maintained. 



iii. Protection of enemies : bats, cuckoos, woodpeckers, crows, 

 starlings, titmice, golden-crested wren, etc. The two latter 



