INSECTS INJURIOUS TO CONIFEROUS TREES. 177 



appearance. Hand picking specimen conifers is to be re- 

 commended, but with an infested area of trees it is very 

 difficult to deal. Lighting a fire to windward of the infested 

 trees, and causing the smoke of coal or creosote to pass over, 

 is an excellent remedy. 



Larch miner {Coleop/wra laricelld) lays its eggs at the 

 end of June on the needles of the larch, the tiny caterpillars 

 mining into and feeding on the interior of these, causing them 

 to turn brown and withered. Living in the tube thus formed 

 during the winter,it changes to a pupa, and ultimately to a moth. 



Bostrichus typog^raphus appears like fine white 

 wool spreading over the stems and branches of several species 

 of conifers. It attacks the Douglas fir, Abies Nordmanniana, 

 A. pectinaia, Pinus Strobus, and several other species. Trees 

 growing under unfavourable conditions suffer most, and the 

 best remedy with infested specimens is to correct these con- 

 ditions. 



Larch aphis {Chermes laricis) attacks the larch, but 

 its depredations are not considerable, 



Sprucegrali aphis {Chermes Abieiz's).— The attacks 

 are confined principally to the common spruce (Picea excelsd), 

 but I have also known P. orientalts, P. sitchensis, and P. nigra 

 to be severely damaged by the same insect. The attacked 

 trees are rendered very unsightly by reason of the cone-like 

 excrescences that are formed at the instigation of the insect 

 on the shoots. It is brought about by the female aphis pierc- 

 ing with her beak or sucker one of the buds, and drawing 

 off the sap, the consequence being an unnatural growth at 

 that part. The only known remedy is to collect the cone- 

 like excrescences and have them destoyed. 



PiSSOdes notata attacks young trees of several species 

 of Pinus, but principally such as are growing under unfavour- 

 able conditions. The eggs are laid on pine trunks, and the 

 larvae feed under the bark. 



Wood wasps {Sirex gigas and 5. juvcncus) are by no 

 means uncommon in the British Isles, and have been found 

 on the larch, spruce, silver fir, and cedars. They are formid- 



M 



