I discovered your wonderful website today and would like your help confirming or correcting my ID of these two damselflies. I photographed them April 4, 2005 in the desert about 1/4 mile east of Topock Marsh, Mohave County, Arizona. I initially identified them as male and female Vivid Dancers – Argia vivida.
Though your photos are very nice, we are not prepared to give more than a possible agreement to your identification. Many species of insects, including Damselflies, need close specimen examination to make a positive identification. This often involves dissection of sexual organs or exact wing veinage assesment. The Vivid Dancer, Argia vivida, is common in the west.
Correction: Sat, Feb 21, 2009 at 3:28 AM
If I may, this is a species of the genus Enallagma (Bluet).
I hope this helps,