Common Sanddragon (Progomphus obscurus)
Detailing the identifying qualities of the Common Sanddragon, including physical features and territorial reach.
Updated: 2/22/2018; Authored By Staff Writer; Content ©www.InsectIdentification.org
The Common Sanddragon is an in-flight hunter, zipping back-and-forth from rest to ambush in mere seconds.
The Common Sanddragon is a dragonfly that prefers moving water. It can be found by streams, creeks and small rivers, flying over and around the water in search of insect prey. It rests on rocks, boulders, logs or branches. On very hot days, raising its long abdomen straight into the air helps it cool off.
Females have a slender dark brown abdomen; males have a slight bulge at the tip of their abdomen. A yellow mark at the top of each abdominal segment adds color to the 'tail'. The front of the face is yellow. Large eyes on the sides of the head vary in color depending on the surroundings. All four transparent wings have a single black bar on the top edge, near the wing's tip. The sides of the thorax have alternating diagonal stripes of yellow, brown and possibly blue.
Females will cruise along the surface of the moving water alone, occasionally dropping a fertilized egg into it by dipping her long abdomen into the water. Once the egg hatches, a young naiad (juvenile) emerges and immediately begins burrowing into the sandy bottom of the stream (and the name 'sanddragon' becomes clear). The stout naiad looks more like a crustacean than a dragonfly, and molts. A naiad eats other aquatic insects and lives underwater. After growing and developing, it crawls from the water, develops wings and becomes a fully mature adult. Adults eat flying insect prey and remain above water for the rest of their lives. They are most active in summer and fall months.