2 August 2015: Observed a male Swift Setwing (Dythemis velox) attempting to perform the perfect obelisk on the banks of Cooper Creek at Avondale Park in Denton, Texas. Avondale Park is administered by the City of Denton, Texas.
The range of Swift Setwing extends over most of the eastern half of the United States and therein especially the Southeast though its range also extends less densely to the west toward New Mexico and Arizona. This is a dragonfly whose range has been expanding according to Odonata Central (the North American online odonatapedia hosted by the University of Texas at Austin) and thus its range continues to change accordingly encompassing more of the United States. It also occurs in Cuba in the Caribbean and in Mexico. Its range does not extend beyond these places to other parts of Central or South America, for example, or apparently other places in the Caribbean outside Cuba.
Dennis R. Paulson and Enrique González Soriano's "Mexican Odonata" online distribution list available since 1994 and revised in June 2015, also notes that Swift Setwing is found in several of the northeastern and northcentral states in Mexico including (alphabetically) Chihuahua, Coahuila, Durango, Nuevo León and Tamaulipas. With the exception of Durango, the other four states all share a border with the United States. Mexican Odonata is hosted by the Slater Museum of Natural History at the University of Puget Sound in Tacoma, Washington.
Swift Setwing's range then is centered in North America and does not generally extend south beyond the Mexican state of Durango or, per Odonata Central's online range map, to the north the limit of its range is marked by sparse sightings in a line of states from west to east including Kansas, Missouri, Illinois, Indiana, Ohio, Kentucky and Virginia. The Great Lakes would appear to be the next stop for Swift Setwing if its migration indeed has contiunued to grow as reported by Odonata Central.
In Texas, John C. Abbott in Dragonflies of Texas: A Field Guide (University of Texas Press, 2015), reports that Swift Setwing is common and occurs in most of the state except for parts of far West Texas and the western areas of the Panhandle. Swift Setwing is trending south surely past Durango in Mexico and headed in a northeastly direction in the United States with Arizona and New Mexico being the exceptions within the Southwest.
A dragonfly of the Americas and the Western Hemisphere, Swift Setwing appears to be widely distributed in those areas where it has already succeeded in making a home. Swift Setwing is an authentic resident of North America.
Eastern Irving, Texas