I love dragonflies, but it will probably be a month or two before they reappear in my area. I bide my time and photograph birds during the winter, but one of my fellow dragonfly enthusiasts, Walter Sanford, has been spending his time studying exuviae, the exoskeletons that are discarded when nymphs almost magically undergo a metamorphosis and emerge as dragonflies. Check out Walter’s most recent posting in which he determined the species of an exuvia I collected last year and be sure to explore the rest of the fantastic photos and info in his blog.
Michael Powell collected several odonate exuviae during a photowalk along the Potomac River in Fairfax County, Virginia USA, including two damselflies and two dragonflies. The exact date is uncertain, although Mike thinks the exuviae were collected sometime between 19-23 July 2017.
Both dragonfly exuviae are from the Family Gomphidae (Clubtails), as indicated by a flat labium that doesn’t cover the face as well as club-like antennae. Notice that abdominal segment nine (S9) is elongated, strongly suggesting this individual is a member of the genus Stylurus.
The dichotomous key for Stylurus larvae that appears on pp. 310-312 in Dragonflies of North America, Third Edition by Needham et al. was used to identify the species of the exuvia. The ninth couplet [9, 9′] is as follows.
9(7’). Length of abdominal segment 9 at least equal to its basal width; lateral spines of abdominal segment 9 at least…
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Mike Powell 