Genitalia and terminal abdominal segments of male basal Hymenoptera (Insecta): morphology and evolution

Abstract

The results of a morphological study of the terminal abdominal segments, particularly the reproductive organs, of male Hymenoptera are presented in the form of 87 morphological characters. The external male genitalia of at least one member of each of the 14 sawfly families are illustrated. The 87 characters comprise sclerites and muscles of the external genitalia, the abdominal sclerites, and the internal reproductive organs. The groundplan of all Hymenoptera and the evolution of the terminal segments of the male genitalia within Hymenoptera are deduced on the basis of a recent simultaneous analysis of basal Hymenoptera which includes the characters from the present work.