DAMAGE CAUSED BY ANIMALS. 149 



73. The small Pine Shoot-boring or Cambial Beetle, Hylesinus 

 (Hylurgus) minor. 



In appearance this beetle may easily be mistaken for H. pini- 

 perda, than which it is about 0'02 inches less in length (i.e., 0'14 to 

 016 inches). It can only be distinguished from that species by not 

 1 1 having any interruption of the process-like excrescences at the 

 extremities of the elytra, and also in being more of a brown, or 

 even reddish-brown colour than deep brown or black. 



But it is much more easy to distinguish between them in their 

 | habits, for whilst H. piniperda forms vertical main galleries, this 



I species forms two horizontal galleries branching one on each side of 



I 1 the entrance-hole; these are chiefly to be found in the thin-barked 

 I upper portions of the trees, and only exceptionally in the parts 



where the bark is thicker. In consequence of this, both the main 

 and the larval galleries are always partially formed in the sapwood, 



! whilst the pupal chambers are entirely within it. 



It prefers to attack sickly standing trees rather than timber 



| lying on the ground, as in the parts thinly covered with bark 

 this latter is apt to dry soon. It is not infrequently the fore- 



! runner of H. piniperda. 



In other respects its life-history closely resembles that of its 

 near relative ; it is probable that it also has a double generation 

 within the year. It likewise becomes injurious in the same way 

 to young shoots when a beetle, and this H. minor is perhaps in 

 one way the more noxious of the two species, owing to ovi- 



1 deposition taking place more frequently in standing trees than in 



I felled stems, thereby leading to interruption of the canopy in 



1 Pine woods. 



It appears to be less widely distributed than H. piniperda, 

 which has a very extensive distribution ; but whilst remaining 

 unknown im many localities, it often occurs in very large 



: numbers in other places. 



Preventive and annihilative measures are practically the same 

 as for H. piniperda ; but owing to the rapidity with which the 

 thin-barked parts of the stem and of poles dry, it is more difficult 

 to operate against it by means of decoy-stems. The latter, too, 

 must be stripped of their bark early, in order to prevent the 

 formation of the pupal chambers in the sapwood. 



