80 INSECTS INJURIOUS TO PINES, ETC. 



distinguished by an upwardly directed point on the last segment ; it 

 bores obliquely towards the heart of the tree in the long axis of the 

 trunk, making a gallery which gradually increases in size, and eventually 

 turns and approaches the surface. At the end of this gallery it changes 

 to a pupa, separated from the outside only by a thin layer of wood 

 or bark, which is gnawed through by the imago upon emergence. The 

 time of development of the larvae is increased by drying of the wood ; 

 and if timber containing larvae is cut up into planks, the insects may 

 eventually emerge in the interior of buildings, etc., and in that case 

 they are stunted and small. 



It is by this injury to otherwise sound timber that the insects are 

 important, but they occasionally complete the destruction of Conifers 

 that would perhaps have lived several years longer. The only remedy 

 against their attacks in a wood which they inhabit consists in careful 

 removal of all infected trees, which are sometimes indicated by the 

 attacks of woodpeckers, and other dead or dying wood in which they 

 can and do breed. Standing trees which -have lost patches of bark 

 by accident should have the wounds tarred over or dressed with a 

 plaster of lime, cow-dung and clay, or other suitable mixture. Timber, 

 when felled, should be removed before the imagos appear in summer. 

 These remedies are also suitable to ward off the attacks of wood- 

 feeding longicorn beetles, as Acanthocinus (vdilis, Callidium riolaceum, 

 etc., which may do a certain amount of damage in a very similar 

 nianner. 



It will be seen that the enemies of the Pine in Great Britain are 

 far more numerous and important than those of any other Conifer. ( )f 

 the sixteen or more species referred to in detail, twelve at least attack 

 the Scots Pine, and of these eight are confined to that tree, and to 

 foreign species of Pinus. The Spruce shares its particular pest, the gall- 

 aphis, with the Larch, which has a special enemy in Coleoplwra laricella. 

 Silver Fir is liable to injury from wood-wasps, but does not exclusively 

 support any important species. This liability of the Pine is 110 doubt 

 due to its being the only forest Conifer indigenous to Britain, where 

 the Spruce is as yet free from the serious enemies which attack it 

 over the greater part of Europe. 



The preventive measures to be adopted against insect-attacks can be 

 gathered from what has been said, but it is necessary again to point 

 out that 110 Conifer-wood can be kept free from the risk of insect- 

 injury unless it is freed from newly dead and dying wood, cut branches, 

 and fresh stumps. There is no need for the systematic removal of the 

 covering of needles, the natural protection to the ground, nor, as a rule, 

 of small twigs and branches much under an inch in diameter. 



It is not rarely objected by those anxious to free a wood from 

 insects that this thorough cleaning is too costly to be put into practice. 

 Without it the insects cannot be kept down, and it is for them to 

 look at the cost of labour and the opportunity for disposal of such 

 timber, and decide whether it is cheaper to let the insects flourish or 

 not. 



The first cleaning-up of a neglected forest is no doubt costly, but 

 after that has taken place there is plenty of evidence to show that 

 systematic and orderly removal of dead wood is profitable in the long 

 run, unless exceptional destruction of timber over scattered areas by 

 storms or snowfall should unduly strain the forest resources. 



