New York Natural Heritage Program
Common Sanddragon
Progomphus obscurus (Rambur, 1842)
Insects

Identifying Characteristics [-]
This is a medium-sized (2") greenish-yellow clubtail, with a handsomely striped or mottled brown thorax. The abdomen has yellow dorsal patches and whitish lateral spots with a moderate terminal club. The wings have yellow leading edges and brown basal spots, the legs are short and dark brown and the eyes are grayish-green (Nikula et al. 2003; Jones et al. 2008).

Characters Most Useful for Identification [-]
The habit of perching on the ground, as well as the combination of basal brown wing spots, a mottled thorax and short legs distinguishes this species from most other clubtails.

Best Life Stage for Proper Identification [-]
Adult.

Behavior [-]
Nymphs tunnel along just beneath the sand, leaving obvious meandering trails like miniature mole tunnels and are a reliable indicator of this species' presence. Adult Sanddragons light on the ground on sunny exposed beaches, with the abdomen raised slightly. Females oviposit along the shores of ponds or in relatively quiet stream riffles, by dunking their abdomens in water and releasing individual eggs (Carpenter 1992). Unlike many other clubtails, this species does not readily perch in trees or shrubs (Jones et al. 2008).

Diet [-]
Adults are aerial generalist insect predators; larvae are also highly predatory.
Common Sanddragon Images
click to enlarge
The Best Time to See
Larvae emerge on the upper Hudson around mid-June, while on Long Island the adults are mostly observed during July. The flight season in New York seems to be significantly earlier than in other northern states where the species is often observed throughout August and the only adults ever observed in the southern Adirondacks (mid 1990s) were seen at the end of July (White et al. 2010).
J F M A M J J A S O N D
Reproducing Larvae present and active
The time of year you would expect to find Common Sanddragon reproducing (blue shading) and larvae present and active (orange shading) in New York.
Similar Species
  • Stream Cruiser (Didymops transversa)
    Stream Cruisers also occur on sandy-bottomed rivers and lakes and superficially resemble Sanddragons. However, they do not readily perch on the ground like Sanddragons, but rather patrol shorelines and sometimes perch on vegetation along the shoreline. In the hand, Stream Cruisers have a single whitish stripe on the side of the thorax as opposed to the mottled thorax of the Sanddragon. Also their eyes meet in a seam on the top of the head rather than being widely spaced in the Sanddragon.