Dr. Steinmann Henrik szerk.: Folia Entomologica Hungarica 23/1-12. (Budapest, 1970)

ROVARTANI KÖZLEMÉNYEK (SERIES NOVA) TOM. XXIII. 1970. Nr. 8. A Comparative Anatomy of the Insect Head II. Muscles and Nerves of the Regio mandibularis and R. maxillaris By Dr. H. Steinmann Hungarian Natural History Museum, Budapest Regio mandibularis (Figs. 1-2) The mandibular region introduces the series of infraoesophageal regions. Whereas the cerebral regions are innervated from the cerebrum or its diverse parts (proto-, deutero- and tritocerebrum) , the main nerves of the infraoesophageal regions originate from the infraoesophageal ganglion. This ganglion emits 4- pairs of main nerve trunks, corresponding to the respective regions or the primordial segments. The mandibular region comprises the area of the mandible and its muscles. Its borders run laterally from the oral opening and on both sides of the face to the occiput. The inferior plane of section borders on the maxilla. The basic structural scheme of the oral organs, consisting of the upper labrum, the mandible (upper jaw), the maxilla (lower jaw), and the lower labrum,underwent various and occasionally extreme modifications in the case of insects. It is mostly the upper labrum which in general retained its role, and the mandible which changed the most. Having been structurally transposed from above to a lateral direction, it is the mandible which assumes the role of gnawing undertaken by the upper and lower jaws of the vertebrates, but whereas these latter function in a vertical direcFol. Ent. Hung., XXIII. 1970. 163