BASIC COORDINATES FOR EXACT DESCRIPTION OF COMPOUND EYES

Using Calliphora erythrocephala, Musca and Drosophila as examples, it was shown that the pattern of the facets of a compound eye can be described as the geometric interference of two systems of concentric circular arcs: with one center located dorsally and the other ventrally. From these two systems an image of the facets of the compound eye can be dipicted in rectangular coordinates. The image yields a quantitatively exact description of the compound eye. It shows the specific symmetry characteristics of the eye and provides an invariant pattern for the arrangement of 1. the rhabdomeres within the ommatidia, 2. the pseudo-pupil and 3. the retina-lamina projection. In addition, angles describing the direction of the optical axis of single retinula cells with respect to the head of the fly are defined. © 1969 Springer-Verlag.