Illinois river cruiser

Illinois river cruiser is a large, slender, 1⅝″ to 3″ long dragonfly.

The thorax is dark brown on the sides and top, iridescent green in front. There is a single yellow vertical stripe on each side of the thorax and no vertical stripe on the front of the thorax. The ridge in front of each wing base (antealar carina) is yellow.

The abdomen is long, slender, and black with yellow spots. Abdominal segment 2 has a yellow ring around it that is interrupted at the top and at the sides. There is a pair of small spots on segments 3 and 4; no spots or very faint spots on segments 5 and 6; one large, conspicuous spot on abdominal segment 7; and often a pair of dash-like spots on segment 8. On the male, segments 7 through 10 are conspicuously swollen, forming a club.

The wings are long, slender, and clear except for a black stigma at the leading edge of each wing. Juveniles often have yellow-tinted wings. Some females have orangish-brown wingtips.

The eyes are bright green and are in contact at the top of the head.

The legs are black.

1⅝″ to 3″ long

Georgia river cruiser (Macromia illinoiensis georgina) is the southern subspecies. It has a half-length yellow stripe in the front of the abdomen. The ring around abdominal segment 2 is continuous, not interrupted. There are conspicuous yellow spots on abdominal segments 3 through 8.

Large lakes, large rivers, large streams

Late June to early September

The female lacks an ovipositor, and must deposit her eggs by flying fast over the surface of the water and washing the eggs off of her body.

Sources

7, 18, 29, 30, 82, 83

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu, 8/2/2025).

Haarstad, J. 1997. The dragonflies of selected eastern Minnesota rivers. Report submitted to the Minnesota Department of Natural Resources. Unpaged.

Steffens, W. P., and W. A. Smith. 1999. Status survey for special concern and endangered dragonflies of Minnesota: population status, inventory and monitoring recommendations. Final report submitted to the Natural Heritage and Nongame Research Program, Minnesota Department of Natural Resources. 54 pp.

Common