A morphological and functional study of the venom apparatus in representatives of some major groups of Hymenoptera

Abstract

An analysis is made of the structure of the venom apparatus, or the more primitive organs by which it may be represented, in 17 species, principally of Australian origin, belonging to the major hymenopterous groups Tenthredinoidea and Siricoidea (Symphyta), Ichneumonoidea(Apocrita-Parasitica), Scolioidea, Vespoidea, Formicoidea, and Apoidea (Apocrita-Aculeata). Consideration is given to the relationship between the venom apparatus of more advanced Hymenoptera and the accessory reproductive glands of other groups of insects. An important link between the two is found to be provided by the Symphyta. Evidence is presented of evolutionary continuity from group to group of Hymenoptera in the relationship of the gland filaments synthesizing venom-type secretion to the reservoir storing it; in the development and degeneration of the musculature of the reservoir wall; and in the relative positions and structure of the endings of the exit ducts from glands belonging to the system. Major changes of form in components of the apparatus are related to what is known of changes in their functions.