144 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



that it is possible to grow in home woods, even when the 

 quahty of the soil is below that of the average type of plantable 

 moorland, poles as suitable for the requirements of the Post 

 Office as those which are produced in the forests of Scandinavia 

 and Russia ; and there is no reason, if the State showed the 

 same zeal in encouraging and assisting afforestation as it has 

 done in helping us to find markets, why the country should not 

 become largely independent of these sources of supply. 



23. A Braconid Parasite on the Pine Weevil, 

 Hylobius abietis.^ 



By J. W. MuNRO, B.Sc.(Agr.), B.Sc.(Arb.),Edin. 



The following notes are the result of observations made on 

 pine weevils and parasites collected in a plantation on the estate 

 of Banchory-Devenick near Aberdeen. The plantation in 

 question was formed in the spring of 191 1, a year after the 

 removal of the old crop, which was a pure wood of Scots pine. 

 The stumps and roots of this old wood afford ideal breeding 

 places for the pine beetle {H. piniperda) and the pine weevil 

 {Hylobius abietis), and they are to be found in considerable 

 numbers. 



The work of the pine weevil is familiar to all interested in 

 forestry. It is harmful only in the adult state and does 

 considerable damage by gnawing the tender bark of young 

 conifers, causing them to wilt and die. Where conifers are not 

 to be got it will readily attack birch, mountain ash and oak. 



In the larval stage Hylobius is harmless. The adult deposits 

 her eggs in or under the bark of the stumps of various conifers 

 but prefers Scots pine. The larva on hatching out commences 

 to tunnel between the bark and the sapwood, and when full 

 grown pupates at the end of this tunnel, either in a cavity or 

 hook gallery in the sapwood, or in a cavity in the bark. The 

 tunnels are filled with frass, consisting of tiny chips of wood 

 bitten out by the larva and passed through its body. 



The whole of the larval life is passed in such a tunnel. In the 

 spring of 191 2 I noticed a few tiny cocoons lying in one of these 

 tunnels, but I attached no importance to them at the time. 

 In July of last year, however, I found several weevil larvae 



' Reprinted from the Annals of Applied Biology, vol. i., No. 2, July 1914. 



