One of two Nearctic species of this genus
The abdomen is short and stocky.
Male: has a red abdomen, typically with black spots above segments 7, 8, and 9. The top of the head and thorax are usually dark blue in mature individuals, ranging from medium blue to black.
Female: Not as colorful as the male; usually shows some dull reddish coloration. Head and thorax are usually a dull brown. Like the male, the female typically has dark spots above segments 7, 8, and 9.
Most common in the Eastern United States, occasionally as far west as Oklahoma and the Dakotas. In Canada, reported from Nova Scotia, Ontario, and Quebec.(1)
Seeps, spring-fed bogs, ponds, occasionally along smaller rivers.
Most common in May, June, and early July.
Despite their color, easily overlooked because of their tiny size and their tendency to hide in thick vegetation.
American Insects site
Several enlarged photos to help ID.
The Dragonflies and Damselflies of New Jersey
Good site even for those outside the Garden State.