SPECIES ID / Invertebrates

True Flies

Mountain Midges


• 6 species known in North America

Phylum: Arthorpoda
Class: Insecta
Order: Diptera
Family: Deuterophlebiidae

Identification Tips:

• 3-6 mm body length
• Flattened body
• Distinct head with forked antennae that are much longer than the head
• 7 pair of fleshy lobes protrude from side of abdomen
• Several rows of tiny hooks encircle lobes

Life History:

• Found in fast mountain streams with high dissolved oxygen
• Occupy cracks and depressions on surface of rocks, usually near water surface
• Usually in currents of greater than 75 cm/second
• Larval stage only lasts a few weeks (persist as eggs for most of year)

• Emerge from pupae in early morning and only live for 1-2 hours
• Several generations per year at low elevation; just one at high elevation

Very Sensitive Somewhat Sensitive Facultative Somewhat Tolerant Very Tolerant

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