98 transactions of royal scottish arboricultural society. 



Forestry Importance of Myelophilus minor, Hart.^ 



A very important investigation has recently been completed 

 by Mr Walter Ritchie, B.Sc, on "The Structure, Bionomics, 

 and Forest Importance of Myelophilus minor, Hart." {Trans- 

 actions of the Royal Society of Edinburgh, vol. lii., part i), the 

 work having been undertaken with the help and guidance of 

 the Society's Hon. Entomologist, Dr R. Stewart MacDougall. 



Foresters are only too well acquainted with the appearance 

 of the common pine beetle and its destructive work, but here 

 we have another species of the genus, hitherto regarded as rare 

 in this country, which has now been found by the author 

 "occurring in very large numbers over an area of 15 square 

 miles in the Aboyne district of Aberdeenshire." This, we may 

 assume, was the area which the investigator found most suitable 

 for his purposes in carrying out the research, and no doubt 

 further investigation will reveal other wide areas equally infected. 

 In any case, it is sufficiently disquieting to know that this new 

 forest pest in Britain occurs in very large numbers over such a 

 wide area, as this is quite sufficient to give rise to a future 

 epidemic. The damage done by bark beetles, which are 

 especially destructive to pine plantations in all stages of growth, 

 consists in their attacking and boring into the shoots of the 

 current year, which are thus destroyed, and also in boring into 

 the stems and tunnelling out their broad galleries in the living bast 

 and cambial regions, which ultimately kills the tree so attacked. 



On the Continent M. ?ninor has been found to attack a 

 number of species of pine ; but as yet in Scotland it has only 

 been found on the Scots pine. 



A large part of the paper is devoted to a careful study of the 

 bionomics of the two species, but what will interest the practical 

 forester most is the means at his disposal to combat their 

 ravages. The damage done to the young shoots by M. minor 

 may be equally bad, if not worse, than that caused by its more 

 commonly known relative M. piniperda. A very important 

 difference between the two species is that M. minor prefers 

 standing trees for brood purposes. It bores into and tunnels 

 out the bark of the higher part of the stem and also of the side 

 branches in preference to the thicker bark on the lower part of 



^In order to avoid confusion, it may be mentioned that Myelophilus is an 

 alternative generic name for Hylurgus ox Hylesiinus of the British catalogue 

 and text-books. — Hon. Ed. 



