INSECT PESTS OF TIMBER 133 



The galleries formed by these beetles in their 

 tunnelUng operations are as characteristic of the 

 insects as is their own structure. We can only 

 deal briefly with this numerous family. 



The Elm Bark Beetle, Scolytus destructor, is 

 one of the worst pests of a notorious family. It 

 attacks Elms with such good purpose as to 

 cause whole sheets of bark to separate from 

 the trees. The closely related Scolytus pruni 

 also attacks Elms, but more frequently Apple, 

 Pear and Plum, also occasionally Hawthorn and 

 Mountain Ash. Scolytus intricatus attacks Oaks 

 and is more common on the Continent than in 

 this country, and it is recorded that 50,000 Oaks 

 were killed by this species in Germany. 



The Black Pine Bast Beetle, Hylastes ater, 

 and its relative, H. jpalliatus, are injurious to 

 Northern Pines. 



Of the British members of the genus, Hyle- 

 sinus, three species, H. crenatus, H. fraxini and 

 H. oleiperda damage Ash, whilst H. vittatus 

 is a pest of Elm. 



Scolytids of the genus Trypodendron bore into 

 the timber and do not confine their attentions 

 to the bark or the subadjacent wood. 



T. lineatum attacks Spruce and Northern Pine ; 

 T. domesticum riddles the timber of Oak, Birch 

 and Beech with its borings. Xyleborus dispar 



