Posts Tagged ‘costa’

Needham’s Skimmer dragonfly (young female)

June 8, 2015

Imagine my excitement when a flash of bright yellow flew past me as I was standing in a small meadow near a vernal pool at Huntley Meadows Park (HMP) — I thought I’d spotted the elusive Yellow-sided Skimmer dragonfly (Libellula flavida)! I say “elusive” because no one I know has ever seen a Yellow-sided Skimmer at the park, although it appears on the Friends of Huntley Meadows Park Odonata species list.

A Needham's Skimmer dragonfly (Libellula needhami) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young female.

22 MAY 2015 | HMP | Needham’s Skimmer (young female)

Now imagine my disappointment when I looked closely at full-size versions of the photos I took — turns out I had seen a young female Needham’s Skimmer dragonfly (Libellula needhami), as indicated by its coloration and terminal appendages. A beautiful specimen nonetheless, but one I have seen many times at several locations.

A Needham's Skimmer dragonfly (Libellula needhami) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young female.

22 MAY 2015 | HMP | Needham’s Skimmer (young female)

Notice the female’s cerci (terminal appendages) are flared in the following photo. I don’t know what the opposite of a “butt crunch” is called, but this is the pictionary definition for the word.

A Needham's Skimmer dragonfly (Libellula needhami) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young female.

22 MAY 2015 | HMP | Needham’s Skimmer (young female)

The last two images in this set are used to illustrate the field marks that enabled me to identify the species for this specimen.

A Needham's Skimmer dragonfly (Libellula needhami) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young female.

22 MAY 2015 | HMP | Needham’s Skimmer (young female)

Wings with veins fairly dark, [ptero]stigma and anteriormost veins yellow except basal part of costa dark before nodus. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 9291-9292). Princeton University Press. Kindle Edition.

The leading edge of a dragonfly wing is called the “costa”; the midpoint of the costa is called the “nodus.” Notice the pterostigmata are yellow and the costa is dark between the thorax and nodus, light between the nodus and wing tip — these are key field marks for Needham’s Skimmer, not Yellow-sided Skimmer.

A Needham's Skimmer dragonfly (Libellula needhami) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young female.

22 MAY 2015 | HMP | Needham’s Skimmer (young female)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Libellula | Libellula needhami | Needham’s Skimmer | female | top view
  • Genus Libellula | Libellula needhami | Needham’s Skimmer | female | side view
  • Genus Libellula | Libellula flavida | Yellow-sided Skimmer | female | top view
  • Genus Libellula | Libellula flavida | Yellow-sided Skimmer | female | side view

Copyright © 2015 Walter Sanford. All rights reserved.


%d bloggers like this: