Helocordulia selysi and Helocordulia uhleri
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Helocordulia selysi (Sely's Sundragon)

Helocordulia uhleri (Uhler's Sundragon)

Above are two comparative photos of the two Helocordulia species in the southeastern US. The orange coloration at the basal wing spot is distinctive for H. uhleri (Uhler's Sundragon), and always lacking on H. selysi (Sely's Sundragon). Also, with close focus binoculars, you can see the form of the terminal appendages. Uhler's appendages are smoothly curved on the outer edges. Sely's has a "tooth" about one-third of the way toward the tip, and curves sharply inward beyond the "tooth".

Bob Barber BBarber@odonate.com - comments are welcome: