APPENDIX. 419 



attention to the value of parasitic insects and other natural enemies, as, 

 for example, Mesolkis auUci(.% a Hymenopterous parasite, together with 

 the suggestion of encouraging certain species of birds, and even voles, 

 which eat the cocoons or perfect insects. As regards voles, it must be 

 remembered they are themselves very injurious to young trees, inas- 

 much as they eat the roots and bark. While recognising that all these 

 suggested remedies have a practical value, T am much inclined to 

 believe that the best remedy is to be found in improved soil con- 

 ditions. This has been very well put forward by Mr J. F. Annand, 

 Lecturer in Forestry, Armstrong College, Newcastle-on-Tyne.^ 



In the Lake district, where this insect is a direful pest, the planting 

 of pure larch has been extensively adopted ; and as regards favouring 

 the insect nothing better could be done. This arises from the fact 

 that in jmre larch crops we get a light canopy which promotes a very 

 grassy surface, thus forming an ideal condition for the cocoons during 

 the whole of the pupal period. On the other hand, where tliere is a 

 mixed wood, or where an exceptional beech-tree, group of beeches, or 

 other shade-bearing trees exist, thus producing a surface of dead foliage 

 (contrasted with the grass referred to), either no cocoons are found or 

 else the cocoons perish long before the pupal period is completed. 



In the Lake district wherever patches are to be found with a bare 

 surface of decaying foliage there is a marked diminution of damage. 

 Hence, from inference, the question arises, how are we to treat our 

 existing woods so as to minimise the damage, or how are we to mix 

 our young woods, in the process of planting, with such a variety of 

 shade-bearing species of trees as will reduce the prospective injuries of 

 this insect 1 In other words, the question arises, what are we to recom- 

 mend on sylvicultural principles as prevention or remedies, either in 

 the formation of young plantations or as treatment in the older 

 woods ? 



It is hoped from the above remarks that the point has been made 

 clear to the effect that the best of all remedies has been in introducing 

 and maintaining such surface conditions as will act in the dual capa- 

 city of being inimical to the development of the pest and stimulating 

 to the crop. To deal with this question at any great length would be 

 equivalent to giving a sylvicultural account of the larch as a forest 

 tree. As this is not intended, the following brief notes are given more 

 from an entomological than a sylvicultural point of view, inasmuch as 

 the entomological aspect should adapt itself to the special peculiarities 

 of crops or the variable intentions of the practical planter. 



Neivly-planted tvoods. — These may be of two kinds — viz., (a) pure, 

 and (6) mixed. 



As regards pure woods, it nu;st be remembered that the larch is a 

 tree with a very light foliage, consequently a grassy surface specially 

 favourable for cocoon development will ensue from the planting of a 

 pure crop of larch. The grassy surface could to some extent be 



^ " Observations on the Large Larch Saw-Fly," ' Quarterly Journal of Forestry,' 

 July 1910. 



