SPECIES ID / Invertebrates

True Flies

Horse Flies/Deer Flies


  • 317 species in North America
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Tabanidae

Identification Tips:

• Body tapered at both ends
• No distinct head; fang-like mouth parts protrude from thorax
• Prolegs arranged around abdominal segments
• No structures at end of abdomen

Life History:

• Larvae found in sediment at the bottom of ponds, marshes and stream pools
• A few species live in riffle gravels
• Burrowing predators; eat aquatic earth worms and other invertebrates
• Larvae crawl out of water to pupate in soil

• Adults are strong fliers, prefer hot conditions, and are only active by day
• Often inflict painful bites on people

Very Sensitive Somewhat Sensitive Facultative Somewhat Tolerant Very Tolerant
      Most Some

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