Chaoborus Midges (image) University of Gothenburg Caption The mandibles of Chaoborus midges range in size from 0.1 to 0.4 millimeters. The mandibles found in lake-bottom sediments are species-specific and show which other Chaoborus midge species were present in the lake in different periods of time. Credit Fredrik Palm Usage Restrictions None 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.