THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands |
Identify taxa Jointed legsSix legsOdonataDragonfliesCorduliidae |
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Corduliidae (emeralds or green-eyed skimmers) |
The emeralds are commonly encountered in the still waters of bogs, marshes, lakes, and cool ponds, as well as slack water in streams. They are easily confused with the common skimmers (Libellulidae), and the diagnostic characters have to be looked at closely to distinguish the two families. As is typical of dragonfly larvae, their body is thick with 5 relatively short points (no plates) at the end of the abdomen. Their labium is scoop shaped and covers much of the front of the head when at rest. The "pincers" or lobes of the labium have a margin of clearly visible (but not overly large) teeth that are all similar in size. The front of the head does not have a small horn or nose. The points at the end of the abdomen are short instead of long. |
Size:
large Identifying feature(s): labium with a margin of medium-sized teeth that are uniform in size; short points at end of abdomen Habitat: wetlands; primarily still waters Tolerance to pollutants: sensitive to tolerant |
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