DAMAGE CAUSED BY ANIMALS. 167 



noting any fall of excrement on the ground during the time whilst 

 caterpillars may be feeding among the foliage, examinations of the 

 soil should also be made here and there about November, after 

 the caterpillars have descended from the trees fojr the purpose 

 of hibernating under the moss, especially in such localities as 

 sandy ridges, or in crops of sickly and backward growth, which 

 are most likely to develop into hot-beds of reproduction. An 

 experimental area should be selected and marked off, and the dead 

 foliage and moss should be removed in order to see how many 

 caterpillars can be collected. Should about 10 to 20 per stem, 

 according to the age of the crop and the size of the trees, be found, 

 one may take it for granted that there are really 4 or 5 times as 

 many actually present, and, in view of the rapid and prolific 

 reproduction of the moth, it will be advisable to take measures for 

 preventing its numerical increase. 



One of the best methods of annihilating this enemy consists in 

 the formation of a ring of tar round each of the stems. This 

 measure was not formerly held in any great repute, as the ordinary 

 tar applied dried up too soon, and it was found practically 

 impossible to go on re-forming girdles to maintain them effective. 

 But, now that it has been found easy to produce a kind of patent 

 viscous tar or caterpillar-glue, at a fairly cheap rate, which will 

 remain sticky and effective for eight weeks and longer, this method 

 of forming narrow rings or girdles of patent tar round each of the 

 stems has recently, although somewhat costly, become almost the 

 sole preventive measure adopted, as it has achieved brilliant 

 results in preventing the continued excessive reproduction of this 

 insect. As the method of carrying out the operation has already 

 been described (vide par. 61), it is unnecessary to repeat the 

 information here. 



The collection of the caterpillars in their winter quarters, 

 formerly held in considerable estimation, has at all times been 

 productive only of unsatisfactory results, as even with the most 

 careful search on the experimental areas themselves, and still more 

 throughout extensive portions of crops, many of the caterpillars, 

 especially of the smaller ones, are apt to get overlooked. Their 

 collection during summer, by knocking or rapping on poles and 

 young trees, so as to throw them down to the ground, is only 

 possible in pole-forest, and even there it is dear, as well as being 

 a very troublesome and ineffective measure. 



