Adult Black Fly (Simulium yahense) with parasite (Onchocerca volvulus) emerging from the insect's antenna. The parasite is responsible for the disease known as River Blindness in Africa. Sample was chemically fixed and critical point dried, then observed using conventional scanning electron microscopy. Magnified 100X. (SEM) Plate #04999. | Electron and Confocal Microscopy Laboratory, Agricultural Research Service, U. S. Department of Agriculture.