Gray Sand Dragon
Progomphus borealis
This dragonfly was photographed along Cave Creek in the Tonto National Forest, Maricopa Co., Arizona on Sept. 22, 2005. This same photo is also hosted at Wikimedia where there are more photos of dragonflies in the family Gomphidae
Gomphidae -- Club-tailed Dragonfly Family
These dragonflies are fairly common along semi-permanent streams in the foothills of the mountains in Upland Sonoran Desert. The last few segments of the tail (abdomen) are enlarged giving the club appearance. While the adults patrol and hunt the air above the streams, the immatures are aquatic hunters below the surface.