The bluets form a group of about 17 similar species in Wisconsin in which the males usually share the characteristics of having blue and black stripes on the thorax, and blue and black markings on the abdomen. In-hand examinations are usually needed to identify them, although they can be grouped into subcategories based on the amount of black showing on the abdomen. Males are easily identified, under magnification, by the shape of their terminal appendages. Females are generally duller than males, and they are more difficult to identify, which is accomplished by subtle differences in the shape of the mesostigmal plates on the top of the thorax. Generally, males are bright blue while the females are green or yellow-green or blue. There are some species that are yellow-orange, a mix of various colors, or black with some blue.
The male of this slender species is a black-type bluet because of its predominantly black abdomen. The slender bluet varies from 1.1 to 1.3 inches. The male's head is mostly pale blue. The pale blue thorax has broad black mid-dorsal stripe and thin black shoulder stripes. The abdomen is mostly black above with a blue tip and black appendages. The female has a similar thorax but pale colors pale blue or tan. Her abdomen has a pale blue tip.
In eastern United States, this species likes permanent ponds and lakes with abundant emergent and aquatic vegetation. In Wisconsin, it is known from just a few central counties.
Throughout its range, the flight season is from late June to mid-August.