part of develops from capable of ocellar triangle ocellus VFB:FBbt_00004505 UBERON:0003161 FBbt:00004505 A simple visual organ on the top of the adult head (Jean-Guillaume and Kumar, 2022). There are three of these per head, arranged in a triangle with one on the midline and the others slightly posterior and lateral (Jean-Guillaume and Kumar, 2022). They develop from the eye discs (Jean-Guillaume and Kumar, 2022). https://www.ento.csiro.au/biology/drosophila/melanogaster.html?ocellus fly_anatomy.ontology photoreceptor external sensillum adult head sensillum presumptive ocellus detection of light stimulus involved in visual perception