152 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



2. Report by R. Stewart MacDougall, M.A., D.Sc, Professor 

 of Biology, New Veterinary College, Edinburgh, Honorary 

 Consulting Entomologist. 



Of the insects sent to me during the past year by members of 

 the Society, only two could be described as great pests, namely, 

 Hylesinus palliatus (Gyll.) and Ilylobius abietis (Linn.). 



Hylesinus palliatus. 



If one were to judge by the mention, or rather the absence of 

 mention, of this insect in our literature of forest insects, the 

 decision would be that palliatus was of little or no importance to 

 the forester. Even on the Continent, where palliatus and its 

 work are well known, the tendency is to minimise the importance 

 of the pest, and to treat it as of only secondary interest. From 

 my observations of this insect, and from what I have seen of its 

 work in the north-east of Scotland, I am convinced that it plays 

 a far more important part as a destroyer in our country than so 

 far has been suspected. I have more than a suspicion, too, that 

 that scourge of our pine woods, Hylesinus piniperda, is confused 

 with //. palliatus, and that in spite of the differences of the two 

 beetles in appearance and in work, some of our foresters credit 

 piniperda not only with its own misdeeds, but those of palliatus 

 as well. 



Hylesinus palliatus is a small beetle, measuring about an eighth 

 of an inch in length. The head and edges of the wing-covers are 

 brown-black or black, while the upper surface of the thorax and 

 wing-covers is brown-red. If the thorax, which is broader than 

 long, and is markedly narrowed in front, be examined with a 

 lens, a number of punctures will be seen, and also a smooth 

 raised line running down its middle. The wing-covers are 

 traversed by fine longitudinal lines, the spaces between which 

 show a number of little knobs and rows of fine hairs. 



The curled yellowish grubs are legless, and have brown heads 

 and biting jaws. 



The grubs infest grown conifers like the pine, spruce, larch 

 (from all of which, in Scotland, I have bred the beetles in scores), 

 and silver fir. One reason, I think, why palliatus is not con- 

 sidered of first importance, is that the beetle is modest in its 

 demands for a breeding-place, not calling for fresh material. 

 That the beetles breed willingly in trunks that have been felled 



