TOMICUS TYPOORAPHUS. 24-5 



trap trees should be barked at latest as soon as pupation of the 

 larvae has occurred, and all the bark must be burned. 



If the barking be longer deferred, some of the beetles will 

 escape, and if it be done too early too many trap-trees will be 

 required, or the beetles will oviposit in standing trees. 



The bark must be carefully removed over cloths, and this 

 should be done on cool moist mornings, as the beetles are 

 then most inert. 



It is not sufficient to expose the bark to the effects of the 

 sun ; this may kill larvae which are really exposed, but in the 

 case of thick bark many would escape, and pupae from which 

 beetles are just ready to emerge would not be killed. 



It is best to burn the bark during cool weather in natural 

 hollows, or in trenches, and to surround them with a wall of 

 glowing embers, so as to kill any beetles which might happen 

 to creep out. The smaller branches and twigs should also 

 be burned, as they generally contain many other smaller 

 but dangerous bark-beetles, such as T. chalcocjrapkus, L. 

 T. itjjHxiraphus, L., may also swarm in the branches. 



It is no use burying the bark at a less depth than IG to 

 18 in., as the beetles can find their way out from shallower pits. 



ii. All standing spruce which shows signs of having been 

 attacked should be felled and barked in June, and the bark 

 burned. 



iii. In the case of a large swarm of these beetles, all trees 

 attacked must be felled, the larger logs barked and the 

 remainder made into firewood or charcoal. All recently 

 attacked trees should be felled first, as the beetles have 

 probably left the trees which have been long attacked. 



Some details may be given of the latest plagues of bark-beetles 

 in the Bavarian and Bohemian forest (1872-70).* In the 

 former about 21,500,000 c. feet of wood was killed in six 

 forest-ranges. The beetles were occasionally so numerous as to 

 obscure the sun. Accompanying T. ti/pographiis, L., were 

 T. chalco(jrai)hus, L., T. intyograplins, Etzb., T. autofjnipJnis, 

 Fab., Hyl. palUatus, Gyll, etc. In the Finsterau range 1,000 

 woodmen were engaged to fell and bark the trees, and, as local 

 labour was insufficient, Bohemians and Italians were recruited 

 for the work. 



