118 PROTECTION OF WOODLANDS. 



velop into vast breeding-places for them. And in order to dis- 

 cover them in time, so as possibily to crush the evil in the bud, dili- 

 gent revision of Pine and Spruce woods in particular is indispensable. 

 Many different kinds of observations lead to their discovery ; 

 bore-holes or bore-dust yield indications on lying timber, whilst 

 the exudation of white drops of resin, or bore-dust hanging on 

 scales of the bark or on cobwebs, give evidence of their presence 

 in standing trees ; excreta and needles, that have been bitten 

 through, are easily distinguishable along paths, or along the drives or 

 open lanes between the compartments containing the different 

 annual crops, especially in the ruts formed by carts; the 

 gradual thinning of the foliage exhibits the destructive progress 

 made by caterpillars ; and even the presence of more insectivorous 

 birds than usual (e.g., cuckoos, starlings, &c.), conveys a plain hint 

 to the thoughtful observer. Excessive breaking up of the surface- 

 soil with their snouts, either by wild-pig or by domestic swine, 

 points to the presence of an unusual number of chrysalides. 

 During the time of swarming, and especially towards evening, 

 the frequency of moths may be readily noted ; whilst during winter 

 the caterpillars, like those of the Pine moth (Gastropacha pini), 

 which hibernate there, may be found by occasionally lifting tip 

 the soil-covering of moss. 



Although, as far as moths are concerned, we must for the most 

 part necessarily confine ourselves to the early discovery of their 

 resence as one of the chief means of obviating damage on an 

 extensive scale, yet, in respect to many kinds of beetles, more 

 effective preventive measures are at our disposal. Thus the re- 

 moval of all sickly stems and windfall timber from the crops, 

 the early removal of coniferous timber, or peeling of the bark at 

 once if it is to be left lying for some time, and grubbing out the 

 stumps of trees utilised, prevent the most dangerous species 

 (Bostrichini, Hylesinini, Curculionidte) from finding the breed- 

 ing-places most favourable to their increase. Decoy-stems 

 may at the same time be laid down here and there in order to 

 attract beetles and weevils occurring in small numbers ; and by 

 destroying the brood when these stems are examined later on, their 

 increase in much larger numbers can thus be prevented. The use 

 of these decoy-stems, to be considered more at length in par. 61, is 

 the best means we have of combating the increase of bark- 

 beetles (Bostrichini) and cambial-beetles (Hylesinini). 





