Laura's Clubtails (Stylurus laurae), Russet-tipped Clubtails (Stylurus larurae), Dragonhunters (Hagenius brevistylus), Common Sanddragons (Progomphus obscurus) and Black-shouldered Spinylegs (Dromogomphus spinosus) were in the process of emerging from the Little Patuxent River yesterday.
Often the remaining cast skins are crusted with sand or mud which makes identification difficult in the field. I therefore always collect all the skins found for identification in the lab -- this also keeps me from accidently counting the same cast skin on consecutive visits to the same site. Two of the most difficult skins to separate are the two species of Stylurus that were emerging from the river at the same time. Their separation is subtle and most of my lab time was spent cleaning, measuring and ultimately identifying between these two species. The other species encountered yesterday were far easier to identify.
Little Patuxent River, Patuxent Research Refuge, Anne Arundel County, Maryland.