424 CONIFERS. 



no means unfrequent in our plantations, the tree, previous 

 to the attack, is always observed to be in an unhealthy 

 state, indicated by diminutive shoots, hide-bound appear- 

 ance and yellow tinge of the foliage, and would eventually 

 die, even if defended from the access of the Hylurgus. 

 In short, the liber, or inner bark of the tree, must be 

 in a certain state of incipient decay, before it becomes a 

 proper food for the larva of the Hylurgus. As soon as 

 a tree falls into this state, it is immediately resorted to 

 by the perfect insects, which bore through the outer bark, 

 and then proceeding in an upright direction, deposit their 

 eggs on each side of the canal they eat out, and from 

 whence each young grub diverges at an angle, and con- 

 tinues to eat its way till full-grown, when it changes 

 into a nymph, and when perfect makes its way through 

 the outer bark. In its imago state this insect also 

 attacks the young shoots of the Pine, entering horizon- 

 tally at the lower part, and excavating its way upwards 

 through the heart of the shoot, and thus destroying it ; 

 but as the side and smaller shoots are generally selected, 

 we have seldom seen any serious injury done to the trees 

 thus attacked. To the same family belongs the genus 

 Tomicus, whose species are also considered to be destruc- 

 tive to the Pine, though we think further observations 

 will probably show that they, like the Hylurgus, are not 

 the proximate cause of decay, but subsequent to it. 

 Amongst the Ceramhycida, or longicom beetles, the Calli- 

 dium striatum is occasionally taken in Scotland, and Rlia- 

 gium hifasciatum we find abundant in old decayed roots 

 and posts of Pine. 



Of the Pinus sylvestris there are several marked varieties 

 in Britain, differing not only in form and habit, but in 

 the size and quality of their timber. In some the wood 



