This large, black-bodied dragonfly varies from 2.3 to 2.6 inches in length. Along the black abdomen, there are pairs of long pointed triangular yellow spots. The thorax usually have 3 lateral yellow stripes with the posterior widest stripe and middle narrowest stripe. The forehead is yellow with sea-green eyes. The male's abdomen is slightly clubbed while the female ovipositor (appendages at end of the abdomen) extends length of a segment beyond abdomen. The female is similar with one exception, the yellow on sides of the abdomen forms almost a continuous stripe.
Ranging throughout northeastern United States and southeastern Canada, the delta-spotted spiketail can be found at sunny seepages and small streams, usually spring runs, including boggy ones. In Wisconsin, it is at the western limit of its range.
The flight season in Wisconsin is not well known, as only a few adults have been documented at one site, in Marinette County, in late June and early July. Throughout its range, the flight season is from mid-May to late August.