More than ever before, there is widespread interest in studying bumble bees and the critical role they play in our ecosystems. Bumble Bees of North America is the first comprehensive guide to North American bumble bees to be published in more than a century. Richly illustrated with color photographs, diagrams, range maps, and graphs of seasonal activity patterns, this guide allows amateur and professional naturalists to identify all 46 bumble bee species found north of Mexico and to understand their ecology and changing geographic distributions. The book draws on the latest research, shows the enormous color variation within species, and guides readers through the many confusing convergences between species. It draws on a large repository of data from museum collections and presents state-of-the-art results on evolutionary relationships, distributions, and ecological roles. Illustrated keys allow identification of color morphs and social castes. A landmark publication, Bumble Bees of North America sets the standard for guides and the study of these important insects.