Black Fly (IMAGE) University of Liverpool Caption This is an 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. Credit Wikipedia. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.