Dragonflies and Damselfies
The key for Odonata can be found in Chapter 5 of the Guide to Aquatic Invertebrates of the Upper Midwest, pages 65-73. Once you have keyed out your insect, you can use the photographs on this website to verify your identification. If you click on the link to each family on the right, you will be directed to a page that has photographs of that family along with close-up photos of their identifying character. The character featured matches the character used in the identification key.
Odonates are separated into two suborders: Zygoptera (Damselflies) and Anisoptera (Dragonflies). Zygoptera have long narrow abdomens with gills coming off the end, whereas Anisoptera are more stout-bodied with no visible gills on the outside of their body.
Left - adult damselfly. Right - adult dragonfly