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Extension > Garden > Insects > Dobsonflies

Dobsonflies

Jeff Hahn, Assistant Extension Entomologist

Published in Yard & Garden Line News, Volume 3, Number 12, August 1, 2001

photo of dobsonfly on a plant

Female dobsonfly
Photo credit: Jeff Hahn

Three inch long, brown insects are probably dobsonflies. They also have long filamentous antennae and conspicuous mandibles. In fact, males have mandibles up to 3/4 inch long, making them look quite fierce and dangerous. Fortunately they do not bite people. The males use their mouthparts for fighting other male dobsonflies.

Dobsonflies are often associated with water as the immature dobsonflies, known as hellgrammites, are found in streams. However, adults are attracted to lights and can be found a distance from water. Dobsonflies are harmless. They are just a curiosity and no control is necessary.

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