Extension > Garden > Diagnose a problem > What insect is this? > General/curiosity insects > Caterpillars, maggots, grubs, and similar immature insects greater than 2 inches long > Hellgrammite

Hellgrammite

Corydalus cornutus

Andrew Williams, Critter Zone

J.F. Butler, University of Florida

Description: 2 - 3 inches long. Large, elongate and somewhat flattened body with 6 legs as well as filaments along its body. Very large mandibles (jaws).

Where/When: Found near running fresh water (e.g. rivers and streams); will come onto dry land to finish their development.

Significance: Not aggressive but may bite if handled carelessly; is otherwise harmless.

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