76 FORESTRY 



Coleoptera 



PINE WEEVIL, Hylobius abietis. The larva or grub (Fig. 

 is harmless, living upon the inner bark of the roots and stumps 

 of recently felled coniferous trees. The pupal (chrysalid) 

 stage (Fig. 13^) is passed in a chamber or depression formed 

 in the sap wood. Altogether the metamorphosis, from egg 

 to perfect insect or imago (Fig. 13^), occupies about fifteen 



c 



FIG. 13. PINE WEEVIL (Hylobius abietis) 

 a. Larva or grub. b. Pupa or chrysalis. c. Imago or adult. 



months. The damage done by the weevils consists in gnaw- 

 ing small patches of bark from the stems of Scots Pine, 

 Spruce, and other conifers, a preference being shown for 

 three- to five-years-old plants. 



The attack is combated with difficulty. To prevent ovi- 

 position, stumps and roots of conifers may be extracted ; or, 

 in order that young plants may not be directly at hand upon 

 the emergence of the weevils, the land may be allowed to lie 

 fallow for a few years, when the stumps will have become 

 old and unattractive for egg-laying. Unfortunately the soil 

 deteriorates if the latter plan be adopted, grass and weed 

 growth spring up to interfere with the process of restocking, 

 and there is the loss in wood increment of the non-productive 

 years. Such considerations may make it advisable to regene- 

 rate the area immediately after the felling and clearance of 

 the old crop, and to depend on remedial measures 



The latter consist of bark traps or pit-fall trenches Small 



