MORPHOLOGY AND EVOLUTION OF THE RHYNCHOTAN HEAD (INSECTA: HEMIPTERA, HOMOPTERA)

Abstract

The structure of the sclerous parts of representative Rhynchota is analyzed and compared with those of Psocoptera and Thysanoptera. Known data on embryology and musculature are also considered in deriving homologies of the structures. The term "suture" is redefined. Standardized terms for the sclerous parts of the head capsules of Rhynchota are recommended and compared with those of previous authors. A phylogenetic synthesis is presented, demonstrating the evolution of the homopterous head capsule through intermediate stages represented in the modern fauna by Psocoptera, Thysanoptera, and Hemiptera–Gymnocerata. Evidence is presented that Coleorrhyncha are related to Hemiptera rather than to Homoptera, that the Gymnocerata and Cryptocerata are natural groups within the Hemiptera and that Cicadomorpha, Aphidomorpha, and Fulgoromorpha are natural groups within the Homoptera.