Dr. Steinmann Henrik szerk.: Folia Entomologica Hungarica 23/1-12. (Budapest, 1970)
The innervation of the insect antennae is typical to such an extent that no considerable deviation from it can be found. The scheme of Pig. 2 represents the innervation of the left antenna. Regio labralis (Pigs. 3-4) The third cerebral region is situated directly below the second one, and thus its upper plane of section may be drawn from the point of meeting of the clypeus and the labrum, decurrent below the antennae and along both sides of the genae posteriorad to the occiput. Its inferior plane of section extends between the ventral margin of the labrum and the dorsal margin of the mandible,and along the inferior border of the genae ,posteriorad to the occiput. In heads of a prognathous type, the posterior (cervical) border of the region may also be considered the median section (above the infraoesophageal ganglion) of the tentorium, invariably along the imaginary plane coinciding with the longitudinal, bilateral median line of the pharynx. This region comprises the tritocerebrum of the central nervous system. In the section called also the tritocerebral region a paired main nerve trunk arises from the tritocerebrum; it is named nervus labrofrontalis since it contains in a common sheath the nervus labralis and the nervus frontalis. Beyond a common stretch, they extend as distinct nerve trunks. I do not discuss these nerve trunks jointly in the present paper, because the nervus labralis belongs to the central, whereas the nervus frontalis to the sympathetic, nervous system. As regards the regional divisions, I propose therefore to treat the nervus frontalis and its nerves when discussing the sympathetic nervous system. The main role of the muscles in the labral region is the moving of the labrum. As Pig. 3 shows, merely 4 muscles can be considered typical in actuating the labrum, namely:
