SPECIES ID / Invertebrates




  • 9 families and 409 species in North America
  • 2 main groups, Dragonflies, and Damselflies

Identification Tips:

• Lower jaw large and hinged to extend outward rapidly
• 3 pair of segmented legs, each ending with 2 claws
• No gills on sides of abdomen

• Dragonfly larvae: Stout body with head narrower than rest of body; Three short stiff spines at end of abdomen
• Damselfly larvae: Body long and slender with head wider than rest of body; Three long flat gills extend from rear of abdomen

• Large head with prominent compound eyes
• 20-85 mm body length
• Wings membranous with many veins

• Dragonflies hold wings horizontally outstretched when at rest
• Damselflies fold wings vertically over back when at rest

Life History:

• Larvae capture prey with extendable lower jaw, adults capture insects in flight
• May crawl, climb to stalk prey or wait, sometimes partially burrowed into mud to ambush
• Dragonfly larvae employ jet propulsion by expelling water from anus

• Most have one year life cycle, but some dragonflies require 2 or 3 years
• Larvae are aquatic, and most live in still waters
• Larvae crawl out of water and adult form bursts out of skin
• Must dry wings for several hours prior to flight

• Adults live a month, on average
• Most mate in flight and eggs are deposited in the water

Very SensitiveSomewhat SensitiveFacultativeSomewhat TolerantVery Tolerant

Primary Information Source:
Voshell, J. Reese. 2002. A Guide to Common Freshwater Invertebrates of North America. McDonald and Woodward Publishing Company. Blacksburg, Virginia.