Genus species (Animalia): Libellula pulchella

The twelve-spotted skimmer (Libellula pulchella) is a common North American skimmer dragonfly, found in southern Canada and in all 48 of the contiguous U.S. states.

It is a large species, at 50 mm (2.0 in) long. Each wing has three brown spots. In adult males, additional white spots form between the brown ones and at the bases of the hindwings; it is sometimes called the ten-spot skimmer for the number of these white spots.

Behavior

This large dragonfly often rests on a prominent perch within its territory. Even when startled it may dart off only to return within a few minutes. The male twelve-spotted patrols his territory and defends it against other male twelve-spotted and even other dragonflies.

Some call this dragonfly the ten-spotted skimmer because the male has ten white spots on his wings (including the two rear wing spots next to the body). However, twelve-spotted is a more accurate name since the female doesn't have the white spots, but does have the twelve dark spots.

Reference: Wikipedia, National Park Service
Photos: P. Needle