The Black Fly (IMAGE) American Chemical Society Caption Scientists have found proteins in the black fly’s saliva that help spread parasites that cause a devastating eye disease. Credit US Department of Agriculture, The Diptera Site 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.