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

m - 7: musculus fronto-tormalis m - 8: musculus fronto-labralis m - 9: musculus compressor labralis anterior m - 10: musculus compressor labralis posterior The actuating of the labrum needs among all oral organs the least number of muscles, since merely a minimal dorso-ventral moving of the upper labral plate has to be done for the sake of covering or freeing the main oral parts. In the mechanism of gnawing, the labrum fills but an inferior role by adjusting the food to the mouth, and it is modified in other oral types. The labral nerve (Fig.

4) contains all nerves in a common sheath, decurrent into one ganglion in some representatives of the insects. The ganglion labrale is therefore generally absent. The diagram shows that 4 of the motoric nerves of the nervus labralis can be considered typical, beside 6 sensory and 1 anastoFig. 3: The typical muscles and nerves of the labrum (Original

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