River cruisers are generally larger and more metallic than the stream cruiser. The blackish royal river cruiser is the largest river cruiser, varying from 3.0 to 3.6 inches in length.The thorax has half-length frontal yellow stripes. The abdomen has small yellow spots dorsally. The male abdomen is not clubbed but does widen toward the end. The females' wings are often tinted yellow turning brown with age. The eyes are green. The female is similar to the male except for the abdomen.
Description of Habitat/Range:
Ranging throughout eastern and southern United States, the royal river cruiser can be found at clean rivers, streams, and lakes. Like the stream cruiser, the larvae may travel more than 40 to 50 feet before emerging. In Wisconsin, this species has mostly been documented on the Mississippi River and seems to prefer medium to large sloughs and occasionally the main channel in areas with wooded or rocky shorelines.
In the northern part of the range, the flight season is from mid-June to early September.