A morphological study of the bark beetle - Dendroctonus monticolae Hopk.

This is a morphological study of the bark beetle Dendroetonus monticolae Hopk. It involves the external anatomy of the adult beetle, the reproductive system and the digestive tract. A discussion of the evolution of the Rhyncbophorous head is given in which the controversial points of various workers are mentioned. An explanation of the hypostoma and the tentorium is given aecording to the writer's interpretation. The thoracic segments are discussed from an outer and an inner aspect. The mesotergum is peculiar in its enlarged precosta and prescutum and specialized scutum and scutellum. The abdomen presents the most important sexual characters which are found in the location and shape of the seventh and eighth terigites. In the female, 8 Is covered by 7, and forms the so-called "pygidium" while in the male 8 is distinct and together with 7 forms the so-called "divided pygidium". It is thought that the ninth and tenth tergites and the ninth and tenth sternites are represented in the sclerotized elements of the reproductive organs. The appendages ot the body are figured with their means of articulation explained. [...