194 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



several interesting examples on larch stumps, I found the eggs 

 laid all round the circumference on the exposed cambium ring. 

 In these special cases, the larvae on hatching tunnelled down- 

 wards for several inches between the bark and wood before 

 beginning their gallery in the wood, afterwards making a 

 separate side gallery that pierced the bark for the removal 

 of frass. Whether or no in more normal cases branch galleries 

 are made to the outside for the evacuation of frass remains for 

 further observation. There is, at any rate, a continued throw 

 out of the bore-meal in the form of pellets, so that the little 

 heaps of white saw-dust which draw the forester's attention to 

 the work of the larvae are not just the result of a boring for 

 entrance. The actual entrance hole is very small and may 

 easily be overlooked, even in smooth-barked trees. The course 

 of the larval gallery varies considerably ; in birch, for example, 

 the larvae tunnelled between the wood and bark for more than 

 8 inches before bodily entering the wood (Plate XV. Fig. 3). 

 In larch, the galleries were confined to the outermost ten rings 

 of wood, and the galleries, which are somewhat curved or 

 bow-like, followed roughly the direction of the annual rings 

 (Fig. 4). In beech, the larvae tunnelled for 7 to 12 inches 

 into and almost at right angles to the wood. 



Winter is passed in the larval condition, full size having 

 not yet been attained. In spring, the larva resumes gnawing 

 and there is a renewal of the out-throw of frass. When almost 

 ready for pupation the larva turns in its tunnel, and makes its 

 way towards the bark, often filling the gallery behind it with frass. 

 Pupation takes place in that part of the gallery nearest the 

 bark ; in thick-barked material the pupal chamber may be 

 entirely in the bark. When ready the beetles enlarge the 

 hole, usually the original entrance, in the bark, and escape 

 into the open. 



Puton suggested that the larvae of Hylecoetus were really 

 useful, their diet being a carnivorous one of harmful bark- 

 boring grubs. No proof exists for this opinion, although a 

 Hylecoetus larva destroyed six Myelophilus piniperda grubs 

 which I introduced into its gallery. 



From an economic standpoint the larvae working in stumps 

 do no harm, yet several times I found them in felled logs. In 

 such cases they would spoil the wood for technical purposes. 

 As eggs are only laid on material that has still the bark on, 



