Bui. 48, Div. of Entomology, U. S. Dept. of Agriculture. 



Plate XVII, 



Work of Timber and Bark-beetles in Spruce. 



a, Work of the spruce timber-beetle in the sapwood of spruce, natural size: b, fungus i Polyporus 

 volvatus) growing from mines of spruce timber-beetle on the surface of the wood after the 

 bark had been removed, natural size: c, work of Phlasotribus pica Hopk. MS. in spruce. 

 (From Bill. 28, n. s., Div. of Entomology, U. S. Dept. of Agriculture.) 



