34 



BULLETIN 1490, U. S. DEPARTMENT OF AGRICULTURE 



stored in closely packed piles for long periods. Af ter the 1st of Feb- 

 ruary logs should be cut up into sizes as small as commercialy prac- 

 ticable and seasoned as promptly as possible ; or sun-cured ; or placed 

 in the mill pond. Narrow strips of bark left on the edges of boards 

 and planks or timber cut from green logs in February and March 

 serve to attract the insects to such places to lay their eggs ; therefore 

 the logs should be trimmed off and the trimmings burned. 



Irregular oval holes from one-fourth to one-half inch in diameter, 

 filled with a mixture of coarse granular and fine powdery frass, 

 found in softwoods, are caused by the " old house borer." 2T (Fig. 35.) 



Fig. 37. — Pitch pockets in western yellow pine, caused by unsuccessful attack, years 

 ago, by the Black Hills beetle (Dendroctonus ponderosae) . A, pitch pockets in 

 sawn board ; B, end of log showing pitch pockets 



It attacks only well-seasoned wood which has been stored for more 

 than a year. This borer continues to work for years, until the wood 

 is thoroughly perforated. 



All bark edges should be removed from lumber and timber; the 

 stock should be inspected frequently for evidences of falling dust, 

 which indicates the presence of these borers, and all such wood should, 

 be promptly burned ; or the stock may be dipped in orthodichloro- 

 benzene, if only slightly injured. 



POWDER POST CAUSED BY FLAT-HEADED BORERS (BUPRESTIDAE) 



In bald cypress in the Eastern States and in western redwoods 

 and cedars, powder-post injury is caused by flat-headed borers. 28 



87 Rylotrupes bajulus L. 



Trachykcle spp. 





