INSECTS INJURIOUS TO CONIFERS. 



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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 develop- 

 ment 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, &c., and in that 

 case are stunted and small. 



The larval jaws are exceedingly powerful, and they have 

 often been known to eat through lead — as in the Crimean war, 

 when bullets were found to have been penetrated by larvae 

 emerging from the unseasoned wood of the ammunition-boxes. 

 A still more remarkable instance is that of the boring of the 

 larvae of S. gigas from the timber supports into the lead-chambers 

 of sulphuric -acid works, so as to let out the dilute acid. 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 cedilis, 

 Callidium molaceum, &c., which may do a certain amount of 

 damage in a very similar manner. 



If the foregoing particulars are summarised 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. Of 

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

 attack the Scotch Pine, and of these eight are confined to that 

 tree, and to foreign species of Piiius. The Spruce shares its 

 particular pest, the gall-aphis, with the Larch, which has a 



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