DAMAGE CAUSED BY ANIMALS. 187 



birds; squirrels and mice devour the contents of the cocoons, 

 whilst swine eat the caterpillars, but do not touch the cocoons. 

 Ichneumon-flies, predatory flies (Asilidss) and beetles (Caralidaz), 

 considerably diminish the number of the caterpillars, which are 

 also particularly sensitive to frost and cold, damp, unseasonable 

 weather, and consequently often die off in large numbers during 

 autumn. 



The annihilative or exterminative remedies, that have from 

 time to time been found necessary, include the collection of the 

 caterpillars when they are crowded together in clusters, although 

 it is by no means always easy to detect their dirty yellowish- 

 green colour against the foliage and twigs. They may either be 

 crushed by pulling the gloved hand firmly along the twigs in the 

 direction of the leading shoots, so as not to injure the foliage, or 

 may be shaken down from the crown when the poles have out- 

 grown the young thicket stage : for crushing the clusters of 

 caterpillars on trees from which they cannot be easily dislodged, 

 nippers have been specially constructed with broad wooden tongues. 



The collection of the cocoons lying on the ground below moss 

 is hardly practicable, as they are so small as to be very easily 

 overlooked. 



The herding of swine in the woods can only be of utility, so 

 far as this insect is concerned, during the short time between the 

 descent of the caterpillar from the stems and the formation of its 

 cocoon-like winter-quarters in autumn, for, as has already been 

 remarked, the pigs will not eat the cocoons. 



Although it will only seldom be of actual occurrence, yet 

 should there be any necessity for felling a crop of young Pine, 

 that may have been totally defoliated by the caterpillars of this 

 insect, a complete and deep overturn of the surface-soil will be 

 advisable, in order to ensure the destruction of the caterpillars 

 and chrysalides lying on and in the ground. 



But in most cases direct and special measures for the exter- 

 mination of this saw-fly will seldom be within the limits of 

 practical adoption. 



89. Cocoon Saw-flies or Foliage-wasps, Lydte. 



The Cocoon Saw-flies are particularly distinguished from the 

 ordinary saw-flies of the genus Lophyrus, by the fact that the 



