9 
THE TROUBLE CAUSED BY INSECTS. 
The evidence obtained from a study of all stages of the afflicted tim- 
ber, including the living, dying, recently dead, and old dead trees, of 
all sizes, and under widely varying conditions of altitude, exposure, 
geological formation, soil, and character of growth, indicates quite 
clearly that this widespread, unhealthy, dying, and dead condition of 
the timber is the work of insects. 
THE PRIMARY ENEMY. 
The evidence found also clearly indicates that the insect which makes 
the first attack on the living trees, and therefore the primary cause of 
the trouble, isa small, black, bark-boring beetle, belonging to a species 
heretofore unknown to science, and appears to be peculiar to the Black 
Hills region.* 
NAME OF THE BEETLE. 
Since this primary enemy has not been distinguished from a number 
of other bark beetles found in the infested trees, it has not been desig- 
Fic. 1.—Work of the pine-destroying beetle of the Black Hills, in inner bark of dead tree. a, pri- 
mary galleries; b, larve mines; ¢, pupze chambers; d, exit holes. Reduced about one-half (original). 
nated by a local name. 1 would therefore suggest that hereafter it be 
designated as ‘‘the pine-destroying beetle of the Black Hills,” and by 
“Since this was written it has been reported from Colorado.—A. D. H. 
