Identification: In the US, occurs locally in Arizona and in the Big Bend area of Texas. Similar to the more common and widespread Pale-faced Clubskimmer. In flight males appear mostly dark gray with a white spot on the upper side of S7. The abdomen is slender and obviously clubbed from S7-S9. There are pale whitish or greenish thoracic stripes and greenish or bluish eyes. In flight appears slender and light weight, giving it a graceful appearance. Distal half of wings often looking milky or cloudy.

Size: Total length: 50-52 mm; hindwing: 38-43 mm.

Similar Species: The clubbed abdomen, color and markings of this species may lead to its misidentifications as a clubtail (Gomphidae), but the eyes are in contact on top of the head. Clubskimmers hang vertically rather than perching horizontally like many clubtails. Tropical dashers (Micrathyria) are much smaller and behave differently. Pale-faced Clubskimmer has a pale face, including forehead (black in Masked). Pale-faced also has a more prominent greenish-white spot on the upper side of S7.

Habitat: Flowing sand and cobble streams in arid mountains.

Natural History: Males of this species typically have small territories that they patrol low over the water, normally less than 1 m but sometimes up to tree height. They can be elusive. It has been described as the most graceful on the wing of any odonate. Flight is steady, smooth and graceful. During the heat of the day this species will patrol a section of stream, remaining on the wing for extended periods. This species hangs vertically, never perching horizontally.

Distribution: Mountains from Mexico to Bolivia, barely reaching the southwestern US. In the US, it occurs on streams on the north and south rims of the Grand Canyon, and Cave Creek Canyon in SE Arizona. It has also been photographed in the Big Bend region of Texas.

David Bell, adapted from https://odonatacentral.org and Dennis Paulson “Dragonflies and Damselflies of the West"