Yearbook U. S. Dept. of Agriculture, 1910. 



PLATE XXIII. 



CZ-- 



WORK OF THE BLACK-HORNED PINE BORER (CALLIDIUM 

 ANTENNATUM). 



[Section of spruce rustic work, showing larval mines on surface 

 of wood, a, Entrance hole of larva into wood. (Original.)] 



