Insect enemies of the pine in the Black Hills forest reserve : an account of results of special investigations, with recommendations for preventing losses . ing Pine. a, Entrance; b, central chamber; c, primary or egg galleries. Reduced about one-half. (Original.) 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, ofall sizes, and under widely varying conditions of altitude, exposure,geological formation, soil, and character of growth, indicates quiteclearl\r that this widespr
Insect enemies of the pine in the Black Hills forest reserve : an account of results of special investigations, with recommendations for preventing losses . ing Pine. a, Entrance; b, central chamber; c, primary or egg galleries. Reduced about one-half. (Original.) 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, ofall sizes, and under widely varying conditions of altitude, exposure,geological formation, soil, and character of growth, indicates quiteclearl\r that this widespread, unhealthy, dying, and dead condition ofthe timber is the work of insects. THE PRIMARY ENEMY. The evidence found also clearly indicates that the insect which makesthe first attack on the living trees, and therefore the primary cause ofthe trouble, is a small, black, bark-boring beetle, belonging to a speciesheretofore unknown to science, and appears to be peculiar to the BlackHills NAME OF THE BEETLE. Since this primary enemy has not been distinguished from a numberof other bark beetles found in the infested trees, it has not been desig-. FlG. 1.—Work of the pine-destroying beetle of the Black Hills, in inner bark of dead tree, a, pri-mary galleries: b, larramines: e, pupre chambers: <K exit holes. Reduced abont one-half (original). nated by a local name. 1 would therefore suggest that hereafter it bedesignated as the pine-destroying beetle of the Black Hills, and by ? Since this was written it has been reported from Colorado.—A. D. H. 10 the technical or Latin name Dendroctonus ponderosa.* The adult ia astout, dark-brown to black beetle, individuals of which vary in lengthfrom -i to 7 mm. (about one-sixth to one-fourth inch). They attackliving and healthy large and small pine trees, enter the bark on themain trunk, and each pair excavates a long, nearly straight, longitudi-nal gallery through the inner bark (PL I and fig. 1), usually groovingthe surface of
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