In this study we compared the anatomy and histology of the alimentary canal of Dentroctonus approximatus Dietz, D. mexicanus Hopkins, D. frontalis Zimmermann, and D. brevicomis LeConte. The results show that these species share similar characteristics, and their structural pattern is comparable to that observed in other Dendroctonus species. These 4 species have characteristics not found in other bark beetle genera in the esophagus, crop, proventriculus, and hindgut. The close relationship of the Malpighian tubules to posterior foregut, anterior midgut, and distal hindgut is also different. Additionally, the midgut of the D. frontalis complex species shows a great cellular diversity, which suggests that this region may be involved in pheromone production.