The Chalk-fronted Corporal (Ladona julia) is a common local skimmer, generally seen from June on throughout the balance of the summer. Both males and females have the "corporal stripes" on the thorax, the pruinescence or bloom on the abdomen indicates this is a male. The brown abdomen with the dark stripe down the middle suggest this male is a juvenile; the abdomen will darken as the dragonfly ages.
The Dot-tailed Whiteface (Leucorrhinia intacta) is another ubiquitous skimmer. Below is a picture of the aptly named male ...
a female ...
and a mating pair.