Excerpt from The Great Basin Naturalist, 1963, Vol. 23 The genus Dendroctonus consists of thirteen American species that range throughout the coniferous forests from Guatemala to the northern limits of tree growth in Canada and Alaska, and one Eur asian species that inhabits spruce forests from northern France to Siberia. All species infest coniferous hosts, principally representa tives of the genera Pinus, Picea, Pseudotsuga and Larix, where their aggressiveness has marked them as the greatest tree killers known. Fantastic losses of standing timber resources, conservatively estimated as averaging more than five billion board feet annually, have resulted from epidemics of these insects. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.