Excerpts from Jim Conrad's
from the July 27, 2014 Newsletter issued from the Frio Canyon Nature Education Center in the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
A good half mile (800m) from the nearest standing water in the little Dry Frio River an unfamiliar dragonfly perched on a dead juniper snag near the top of our hill. Any dragonfly on a wooded slope so far from water is unusual, plus this one was boldly colored in a way I hadn't seen, so I worked hard to get the picture shown at http://www.backyardnature.net/n/14/140727df.jpg.
With such striking markings -- especially the thorax so brightly yellow on the sides, the dark "shoulder bands" above, and the long hairs on the legs -- in my Dragonflies through Binoculars field guide by Sidney Dunkle it was easy to peg this as the Black-shouldered Spinyleg, Dromogomphus spinosus, a species described as common in eastern North America.
However, as good ol' volunteer identifier Bea in Ontario was good enough to point out, that ID was wrong. The fundamental error was that our hillside species is not a dragonfly, but rather a damselfly, albeit a member of the Spreadwing Family, the Lestidae, who at rest spread their wings like dragonflies, instead of folding them neatly over their backs like decent damselflies. Bea's reckoning is that this is the Plateau Spreadwing, LESTES ALACER. in the US known from Texas, New Mexico and Arizona. Our Plateau Spreadwing is a female -- the male looking quite different -- and one wonders whether Nature has been at work evolving the two unrelated forms to look so similar!
I find very little about this species on the Internet. At least here we can say that in late July in this part of the world females turn up near the tops of very dry hills covered with scrubby junipers and oaks, and at least that's something.