riverine clubtail

riverine clubtail (Stylurus amnicola) [male]
Photo © Mary Kay Rubey

FEATURES
The riverine clubtail is a little less than 2 inches long; has large, black-veined wings; distinct thoracic marks; and a moderate club. Males have dark blue eyes on a green face with irregular markings, and they are mostly black all over with light green-blue and yellow-green color. They have a complex thorax pattern that looks like a capital-letter “I” with two ovals on each side. The abdomen mostly black with long, thin, blue-green stripe down back. Females are like males, but stripe on top of abdomen is complete. Like the black-shouldered spinyleg (Dromogomphus spinosus) but is smaller, shorter-legs, wider club, and more yellow than black on sides.

BEHAVIORS
They can be seen statewide in Illinois from June to September. Winged adults haunt medium to large rivers and are rarely seen during emergence except when breeding. They spend most of their time in treetops, except when breeding. Males cruise up and down the river channel for short periods of time. Little is known is about their breeding and feeding habits. 

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Odonata
Family: Gomphidae