AppearanceThe adults grow up to 65 millimetres long and can be encountered close to running water and lakes from mid April through late August. The eyes of ''Onychogomphus uncatus'' are widely separated and bright-blue or gray-blue eyes, never green. The front black line on the side of the thorax does not touch the midline. The yellow collar at the front of the thorax is interrupted by a black bar. It has four cells on the anal triangle of the rear wing, but no yellow line on the 'vertex'. Cercoids are always yellow. Their life cycle lasts about three years.
Some text fragments are auto parsed from Wikipedia.