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chaptp:k III. 



ON SOME METHODS BY WHICH THE PRESENCE OF 

 INSECT PESTS IN THE FOREST MAY BE ASCER- 

 TAINED, AND THEIR LIFE HISTORIES AND MODES 

 OF ATTACKING TREES STUDIED. 



One of the commonest ways in which forest insects bring themselves 

 into prominence, and one which must have made itself evident to all 

 forest officers, is by entering the bungalow at night, owing to the attraction 

 lights have for this class of animal life. Now, information of a very 

 important nature may be gained from these nocturnal visitations : I mean 

 of importance to the forester, for the appearance of a particular insect 

 signifies that at this period of the year it has arrived at the mature stage 

 of its metamorphosis, and that it is now probably engaged in egg-laying 

 in the forest, and for this purpose, if a tree pest, is in search of trees in 

 a state suitable for its requirements. Thus, by noting these dates of appear- 

 ance we secure some very important information — first, in many cases, the 

 date of appearance of the insect on the wing, or one of these dates should 

 the particular insect pass through more than one generation or life-cycle 

 in the year; secondly, the date or approximate date on which the eggs 

 are laid in the trees, since in many cases but a short period is passed 

 in the mature stage of its existence by the insect, the longer period being 

 in either the egg, grub (uiost usual), or pupa period of its metamorphosis ; 

 thirdly, we may, and very often do, secure the approximate date on which 

 the young grubs or larvae hatch out from the eggs, observation having 

 shown that in miny cases, notably in the case of the m jre dangerous of 

 the wood- and bark-boring beetles, but a short period, often forty-eight to 

 sixty hours or even less, elapses between the deposition of the egg and 

 the hatching out of the grub from it. 



We thus see that even the appearance of a particular species or 

 several species at the office or dinner-table may, if taken advantage of and 

 provided the specimen is kept and its identification secured, lead to informa- 

 tion of the highest importance to the forester being placed upon record. 



Similar observations may be made whilst engaged in executive 

 work in the forest. An insect which makes its presence noteworthy 

 in a locality owing to its abundance or for any other reason should be 

 at once secured ; the date of collection, locality, and class of forest, 

 with species of trees it was frequenting or appeared to be frequent- 

 ing, should be at once noted down, and every effort made to 

 ensure the identification of the species. It is almost impossible for 



