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NEW YORK STATE MUSEUM 



Spruce bark beetle 



Polygraphus rufipcnnis Kirby 

 A light brown or black, rather stout beetle about 3/ 33 inch in length makes somewhat 

 irregular transverse galleries, from which diverge smaller dilating larval galleries, in the 

 inner bark of spruce. 



This very common species in the Adirondacks is a dangerous enemy 

 of the spruce. It can usually be found in small numbers in this tree and it 

 is frequently present in great abundance in the bark of cut logs or 

 trimmings. This bark borer was taken by the writer in 1900 in several 

 localities in the Adirondacks. It was found Aug. 14, 1900, in all stages in 

 the bark of cut spruce logs and some nearby fallen spruce were badly 

 infested by the insect. It was present Aug. 22 at Axton, breeding in large 

 numbers in logs cut sometime during the preceding month. Old beetles 

 were scarce at this time and there were numerous larvae and few pupae, 

 indicating that the infestation was a comparatively recent one. This insect 

 was also found at work in considerable numbers in spruce tops cut between 

 September and December of the preceding year, and remains of this species 

 were found under the bark of dead spruces standing on the edge of Little 

 Clear pond at Saranac Inn. Large numbers of trees had been affected in 

 in this manner and the primary cause of the trouble in this particular 

 instance was probably the raising of the level of the pond, which had 

 occurred several years earlier. This borer was found by the writer 

 associated with species of Dryocoetes in spruce and with Tomicus 

 balsameus Lec. in balsam, and Dr Hopkins records finding a single 

 example in pine. 



Early history. Very little has apparently been recorded concerning 

 this borer aside from the facts made known by Dr A. D. Hopkins who has 

 made an exhaustive study of this insect in West Virginia, and writing of it 

 in 1893, states that it infests black spruce. His studies led him to believe 

 that it was a very dangerous enemy of this tree and that it may have been 

 the species to blame for the great destruction of spruce timber in West 

 Virginia in 1883 to 1885. 



