1. The aquatic larva of a dobsonfly, having a long dark body with pincers and gill filaments, commonly used as fishing bait.
Usage: plural form; chiefly North American; also called alderfly larva

Examples

• Anglers often dig for hellgrammites under rocks in streams to use as bait.
• The hellgrammites clung to the underside of the log in the creek.
• Many fishermen prefer hellgrammites because they are hardy and attractive to large fish.
• We collected several hellgrammites from the riverbed for our fishing trip.
• The dark, segmented body of a hellgrammite makes it an effective lure for bass and catfish.