What's That Bug? does not endorse extermination

Centipede-like bug with pincers?
Location:  Utah
September 2, 2010 1:26 am
I have been searching long and hard for a site where I could ask about a bug I found, so here goes!
Unfortunately I don’t have a picture (but I drew it? haha) of it since I was too frightened to catch it and I didnt have my camera with me at the time.
It was also very dark when I found it and I was in a river… I was swimming around, looking for tadpoles and frogs. And then much to my horror I shined my flashlight upon something that was definitely neither of those.
I can’t remember exactly what it looked like but it had a very long centipede-like body with a lot of legs like one. I think it was white and black (but it was nighttime, and I wasn’t really paying attention to its color for obvious reasons) and it was coming out from under a rock. So it obviously lives in the water. And it had very sharp needle-like pincers that curved in and looked like it could chop your finger off if it got close enough.
I’ve looked everywhere for one. All over the internet, and I can’t seem to find anything that looks even remotely close to it. I really wish I had taken a picture of it! Does something like this exist? Or is it some freak science-experiment gone wrong?
I’m sorry, I wish I had a better explanation of what it looked like (and a better drawing!). The next day I went back hoping to catch it but I didn’t see it anywhere. Of course it only shows up when it isn’t wanted.
Signature:  Maddie

Possibly a Hellgrammite

Hi Maddie,
We were quite certain based on your drawing and your letter that you had an encounter with a Hellgrammite, the aquatic larva of a Dobsonfly, but we began to question that theory when we realized your sighting was in Utah.  The commonly encountered Eastern Dobsonfly does not range to Utah, but there are three other species that occur in western states.  According to BugGuide:
“The only eastern species is Eastern Dobsonfly,
Corydalus cornutus. Three other species apparently have very limited distribution in North America:
Corydalus luteus – South Texas
Corydalus texana – SW US west of the Rocky Mountains
Corydalus bidenticulatus – Arizona
Genus is restricted to the New World–other species in Central and South America
.”
We were unable to locate an image of a Western Dobsonfly,
Corydalus texana, but a web search did lead us to a trout fishing page with a photograph of a Dobsonfly and a nice description.  The God of Insects website also has some information.  We are posting your letter with an image of the Hellgrammite of an Eastern Dobsonfly as we imagine the western counterpart must look very similar.

Hellgrammite

Interestingly, we did notice that one of our earlier postings is from Colorado, which would indicate there is a strong possibility that image is of Corydalus texana.

What's That Bug? does not endorse extermination

9 Responses to Possibly an encounter with a Hellgrammite

  1. Larisa says:

    We had one of these crawling on our tent the other night near the Colorado River, 7 miles NW of Moab, UT. Scary looking guy.

  2. Cody awe says:

    I found somthing simular in color and species here in iowa back when we had very bad flooding eccept we caught one and it had hind pincers and was very fast and aggressive it might have been a hellgrammite species.

  3. Will says:

    Dear friends, I have encountered that exact same insect and had video of it. I will dig it up if you ask it was 4 years ago and I have been searching ever since. Only thing is I saw it along the Delaware river just north of Easton Pennsylvania with my family. I took note because it seemed aggressive and it ran near my stepson. It’s size was large to me at the time, seemed to be rough guess 6 to 8 inchest long but looks exactly like the picture.

  4. Mike cushing says:

    I saw one of these in vermont while trying to find a crayfish to use as bait…..it was under a rock tried to get a pic but lost it in the Rapids I didn’t want to touch it cause didn’t know what the he’ll it was

  5. wayne courts says:

    We always called them leatherheads where I grew up in northern California. They are great for catching trout in the creeks. We always called salmonfly nymphs hellgermites.

    • bugman says:

      Thanks for providing an alternative spelling for Hellgrammite, a name with a murky origin, though the sound of the name is quite fitting for the creature.

  6. Graham Milner says:

    So is it a Hellgramite? We just caught one in my garage and I need to know if I should just burn down the garage or if it would be safer to burn down the entire block. So far it is still alive because none of us have the fortitude required to enter into battle with it. Really would like a solid answer as to what this thing is.
    Update: As I was typing this up my friend Taco Dave went after it with a blow torch and a throwing axe. It is still alive and well but Taco Dave is not. Well he’s alive but he is not the same person he was going into this. He is pacing around outside repeating the phrase “Ive seen things man”. Taco’s little brother Burrito Bob is suiting up next. He has chosen a garden shovel and a 5lb sledge hammer. Update coming once the battle has ended. Send help if I dont post a reply within 45 minutes. There is a school 500 yards away ,the ball field can handle helicopters and some jets with short take off and landing capabilities. If we dont reply to people yelling within 5 minutes let the napalm fly. Godspeed

  7. kira says:

    We found two of these in Dinosaur National Monument this past weekend. We were in Utah and on the Green River. They were both long, fast and somewhat agressive. we do have a picture but its very similar to the one you have.

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