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



Plate XII, 



Fig. 1.— Cocoons of Bracon simplex, a 

 Parasite of the Spruce-destroying 

 Beetle. 



The cocoons of Bracon simplex, in the larval 

 mines of Dendroctonas piefaperda. are shown 

 at a. (From Bui. 28. n. s.. Div. of Entomol- 

 ogy, U. S. Dept. of Agriculture.) 



Fig. 2.— Work of the Pine-destroying 

 Beetle of the Black Hills. 



a, Pitch tubes on surface of bark, much re- 

 ducer!: b. same, two-thirds natural size, 

 i From Yearbook, U. S. Dept. of Agriculture, 

 1902.) 



