DAMAGE CAUSED BY ANIMALS. 12] 



year. For such decoy-stems, dominated or suppressed, but still 

 healthy, poles, or stems should be selected, and not half-dry ones, 

 that are already nearly dead, as such lose their efficacy too soon. 

 It is also a good thing to provide them with rests below, so that 

 beetles and weevils may have access to every part of the stem, 

 especially to the lower side which remains fresh and sappy longest ; 

 and, at the same time, the branches (which also form decoy breed- 

 ing-places for many species) should be removed by lopping, in order 

 to diminish the evaporation that otherwise takes places through 

 the leaves. If timber from the winter's fall is still lying about 

 in the woods, it can, in the same way, be utilised for decoy pur- 

 poses. But care must in that case be taken to see that it is re- 

 moved from the forest by about the middle of May, and that it is 

 not merely taken to be stored at some saw-mill in the vicinity of 

 woodlands, for it should be treated exactly in the same way as other 

 decoy-stems, by being duly peeled and the bark being burned. 



Decoy-stems must be examined carefully from time to time, in 

 order to see if they have been utilised by insects for breeding 

 purposes. This can be seen from exudation of resin at the punc- 

 tures, or from small heaps of bore-dust lying on the bark ; pieces 

 of the latter should also be removed here and there to ascertain 

 to what stage the young brood has developed. If development 

 has proceeded so far that the largest larvae are fully half-grown, 

 the decoy-stems should be stripped of their bark; for if it be 

 removed before then, there is always the danger of a good many 

 females being still occupied in ovi-deposition throughout the stem, 

 and these might still be able to go and breed elsewhere if the bark- 

 ing is carried out too soon. It is best to burn the bark containing 

 the young brood, although the Iarva3 soon die if the pieces of bark 

 i be exposed to the sun with the sappy, cambial layer upwards on 

 warm sunny days, provided always that the development of the 

 insects has not gone so far as the pupal stage. Branches and 

 twigs that have become infested had best be burned. 



Collecting the larvas, as may sometimes be done in the case of 

 moths, is really only possible with regard to cockchafer grubs 

 in nurseries, when the soil is being prepared for seed. But on the 

 other hand, many kinds of the larger beetles, like cockchafers and 

 Spanish flies (Lytta vesicatoria), may be collected and killed after 

 shaking the crowns of young poles or trees, or by means of decoy 

 bundles of twigs or bark to which the beetles are attracted, or 



