Morphologische regionale differenzierungen der retina und des facettenrasters vom komplexauge der Pipunculidae (Diptera : Cyclorrhapha): ein neuartiges retinales muster der fliegen (Brachycera). [Morphological differentiation of retinal regions of the com

The retinae of the compound eyes of several species of Pipunculidae (Diptera: Cyclorrhapha), belonging to the subfamilies Chalarinae and Pipunculinae, were investigated in semithin sections in both sexes of the representative species. Whereas the boundary of the dorsal and ventral retinular cells in a mirror-image configuration is at the equator in the male, in the female it is situated in the anterior of the eye at the level of the upper frons, and is located above the equator only in the lateral region. In the frontal view, it constitutes a concave arch to frontofacial region. The facets of the corneal lenses are strikingly enlarged in the anterior region of the eyes, compared with those in the remainder of the eye in the female. This area with the large-faceted ommatidia, was determined in more detail in total views as well as in histological preparations and compared with the eye of the male. In the frontal region, the mirror-image boundary in the retina of the female coincides exactly with the boundary between the large-faceted central and small-faceted peripheral ommatidia. By examining the dichoptic eyes of the Chalarus male, it has been demonstrated that the arcuate mirror-image boundary in the retinae of females is not associated with their dichoptic eye position. This is an example of sexual dimorphism. The retinal pattern of the female described in this paper was not found in other 37 families of the flies investigated till now. This new type of the retina of the suborder Brachycera (including Cyclorrhapha) is to be subsumed under the synapomorphic ground plans of the Pipunculidae. At the same time, it proves to be an autapomorphic characteristic of the family.