What's That Bug? does not endorse extermination

Can you identify this?
I found this in forest litter in foothills of Colorado at about 8000 ft. elevation last fall. I saw several of them glowing green in the dark and was able to find a couple and photograph them. I am attaching several photo’s and from looking at your site it may be a firefly, but I have lived here for 45 years and have never seen these before. I appreciate any information you can provide as to what this is. I can’t believe I found this web site and still have the photo! Thanks!
Bill Trust

Hi Bill,
We wrote to Eric Eaton to see if he knew a species name for your Glowworm. We wrote back saying he would check with another expert. Here is Eric’s query followed by the expert’s thoughts: “Q Dear Art: I did not know there was anything like this in Colorado! Any ideas? A John Wagener Green revised Microphotus in 1959 (Coleopterists Bulletin 13: 80-96). The only species he lists from Colorado is Microphotus pecosensis Fall. Fall described this species in 1912 from specimens collected in June and July in New Mexico. Green also recorded this species from Arizona, California, Texas, Utah, and Chihuahua. His Colorado records include Royal Gorge, Junction Creek, San Luis Valley, and Stollsheimer. He notes that they were all females collected in June and July and that, although their identities are not certain, they are probably pecosensis. The pink females are said to closely resemble the more common CA species, M. angustus LeConte and have 6-segmented antennae, 4-segmented tarsi. The CO specimens all have 3-segmented “

Update:  June 12, 2018
Based on a brand new posting, we realized we never changed the subject line of this posting to correctly identify this as a Firefly and not a true Glowworm.

What's That Bug? does not endorse extermination
Location: Colorado

58 Responses to Firefly, NOT Glowworm from Colorado

  1. Teyalora says:

    We have found the same creature in Manitou Springs at 7000ft. They glow green, and look generally the same. Do you think their is a possibility that they could be moving up into the mountains?

  2. mlmalo2 says:

    We have outside tonight @ about 8000ft in pine junction, co. Never heard of one before tonight. Like a lightning bug that crawls.

    • tom says:

      I found one in Pine Co. on June 20th 2015 @ around 9:45pm. Never knew they existed but we got some pics and video—super cool!!!

  3. Brandon says:

    I just found one of these last night (4th of July) as I was on a night hike up Massey Draw in the Ken Caryl valley right next to the Foothills (approx. 7,000 ft. elevation). I saw something glowing in the distance on a rock, I thought it was a firefly but when I approached it and shined my light on it it was a little pink worm with a glowing green end (head or tail in not sure). I took a picture but I couldn’t get my camera to focus on it in the dark, but you can tell it’s the same as the worm above. I asked my dad what it was in the morning and he said he has never heard of glow worms in Colorado and he has lived and hiked here for over 60 years.

  4. me and my friend Scott found a glow worm at 8,000 feet also it has to be the same species we are going to look for more this yearand try to classify it

  5. I’ve seen this larval-looking female Microphotus pecosensis several times at 6000 ft. in Oak Creek Canyon, south of Flagstaff, AZ. I didn’t know there was a fire fly that didn’t flash while flying. A friend just found one a few nights ago about 7300 ft. on the slope of Mt. Elden on the north side of Flagstaff. As he watched, two adult males came and mated with the female.

  6. joel crass says:

    Two nights ago, a friend and I found several glowworms at about 8,000 foot outside of Woodland Park. I had never seen any before. They were cool.

  7. michael browning says:

    this is too funny,so I am looking online to find info on glow worms in Colorado and I find this site and see that my friend joel has already left a comment!!!we did see several glow worms near rampart res.I have lived here 20 yrs and never saw them until now

  8. Natalie Longsine says:

    For the last couple of nights looking out of our bedroom window…rt there on the ground we saw 3 green glowing lights. Both my husband and son went with flash lights to investigate. They said the bugs were like tiny worms with the heads lit up..,what are they & there in the same spot even to night.

  9. Eric says:

    I was coming down Barr Trail (Manitou Springs) and saw several of these worms. They seem to like the scrub oak.

  10. Dale says:

    We saw one in Buffalo Creek, CO (~6,800 ft) on July 11, 2014.
    I have some good pic.s but don’t know how to post them here.

  11. Brett says:

    I was actually digging in our garden last night in Lehi, UT (~4,000 ft?) and found something similar. At first I thought I was hitting rocks with my shovel and causing sparks, but then realized it was actually these glowing grub-like creatures. Tiny, about the size of the tip of a ball-point pen, glowing green. I’ve lived in the intermountain west my whole life and I’ve never seen anything like them. Wish I would’ve taken a photo. If what I saw is the same as the Colorado glowworm, what does it grow up to be? Or is the worm stage it’s mature, adult stage? (bug newby)

  12. Marco Davis says:

    Found one last night in Orem UT (just 20 miles south of Lehi, see post above), and about 4500 ft elevation. It isn’t as developed as the critter shown in the original post, but the green glowing tip is pretty eerie as you weed in the garden just after dusk! I’ll upload some pictures.

  13. Dutch says:

    We live at 9500′ elevation near Hartsel, CO and noticed a strange glow off our deck while star watching. We got out our flashlight and tracked down the light source, it was a very tiny, (1/4″) long and worm looking. It has been on te same rock for 2 nights now.

  14. Dru Majors says:

    We saw 2 glow worms while camping in the Rampart range just West of Devils Head. They were glowing flourecent green. Half the body was yellow and the other half pink. I have lived here and explored Colorados mountains for 35 years and have never seen them before.

  15. These glowworms are looking peculiar. I am also seeing this type of worm for the first time. People mentioned that they have seen this worm in mountain regions. Only a few people go to mountains and found them. so, it would be a strange one to the people living in the region. The experts might be got the name of this worm.

  16. David says:

    I have seen two of these creatures or something similar here in South Carolina at an elevation of only 292 feet. Never seen these before tonight!

  17. Such an inspiration!

  18. Mike Kaiser says:

    I live just out side of Williams AZ at about 6800 ft. For the first time we have this bug. Never have seen it before. We found quite a few of them. The date 6-21-16 time 9:26pm. Red with green glow.

  19. I just came upon a bright light while out hiking on a July night outside Saguache in the San Luis Valley–over 9,000 feet. Upon close inspection I discovered a tiny, pink worm with an illuminated tail embedded in the embankment along side the dirt road! I’ve never seen anything like it. Such a dazzling light in the moonless night.

  20. June Cahill says:

    I just found one on my flagstone patio! I live in the foothills of Tucson,AZ. All lights off, and looked down to see a tiny green glowing light. Gently picked up with a soft towel -a tiny little pink worm with green glowing head. (Or tail) I brought it inside to investigate further, and with the light on, the creature’s green light went off! I took it back outside (dark) and after a few minutes, the green light was back again! Never seen before. 10:30pm, July 15, 2016. I took photos-will try to upload tomorrow!

  21. Alex Kaulbach says:

    Saw one on a rock in Wlidcat Canyon near Lake George, Colorado, then found at least 5 more that night further up river, July 16th, 2016. Been hiking and camping CO for 20 years, live close to Pine Junction, never seen them. Very cool!

  22. Don Kargo says:

    Saw numerous glow worms at Mueller State Park, outside of Divide, Colorado, last summer around July 4th. Each one we found were were situated exactly in the middle of the cement parking curbs in the campground. Don’t know if this could be attributed to some kind of temperature preference for the glow worm…

  23. Jonathan stringer says:

    Just saw one of these little guys on a overnight camping trip just north of Payson AZ below the Mogollon Rim / See canyon , They are bright on a dark night , It was in the red rocks at about 6,000 ft. First time I had ever seen. Thank you all for your information , I had never seen one befor then .

  24. Rick says:

    Four were in back yard last night. I live at the West End of Manitou Springs.

  25. Amy Archer says:

    I saw one of these in the mountains on 6/15/2017 on a rock at first i thought it was reflection from the fire but i grabbed a flash light and had to check it out sure enough a worm. First time ever seening one i found him in the mountains north west of saguache colorado

  26. Jack Slagle says:

    We were standing on our deck last night and saw a single glowing light on a rock in our backyard. When we investigated we found one pink glowworm. We live at 6,475 feet in the foothills of the Wet Mountains near Florence, CO. If we find more we will photograph and post. Have never heard of nor seen any of these in my 42 years of exploring Colorado.

  27. Randy P says:

    Sighted these on Mt. Charleston just north of Las Vegas NV. Probably around 8500 ft of elevation.

  28. David C V says:

    Saw one tonight in Tucson, AZ. Got a small video on it. Light just went out after five minutes but the worm continued to crawl. It was dark out. Probably 2400 ft above sea level.

  29. NICK JOHNSON says:

    At my parents house in Colorado Springs there is a tree in their backyard that has these green glowing lights. we’ve seen them the past couple of years but only in this one type of tree. (no clue what kind) but last night I counted about 15-20 green ones and 1 red one. they seem to appear every year right before it gets cold. Is there any definite answer as to what these are?

  30. Ben Gillock says:

    I saw one of these a few years back (2014), 6500 ft elevation, Montezuma, NM. Never seen one before, never seen one since

  31. Van Peters says:

    Our house is at 6600′ near Mountainair, NM. I have seen 3 of these beatles, so they are in central New Mexico. Interestingly one was on our patio in February when it was below freezing!

  32. Chad M says:

    My wife and I saw several of these insects glowing together on a rock in our yard this evening. Lived here for 11 years, and this is the first time we’ve seen them. We live in Woodland Park, CO @ 8,700 feet. Fire fly makes sense – they do seem to be in a larva stage. Although, we’ve never seen any actual mature flies at night at this altitude -we don’t even hear crickets at night (something I miss terribly, since moving from the east coast).

  33. Paul C says:

    Spotted one last night at 8200′ (Sampson Mountain) in Jefferson county, Colorado. First I have seen since moving here 12 years ago. Very bright glow.

  34. Cathy Frey says:

    Saw and have photos of a presumed female in Santa Fe, NM on July 14, 2018. Bright constant glow. Have not seen one before in the 20 years living here.

  35. Andrea says:

    Saw a couple of these exact bugs in Bandelier National Park this past weekend. Rangers said they were “glowworms” but I was skeptical. Glad to have found this site and learn their real name. Not sure why they are called fireflies or glowworms. The green light from their tail end looks just like the fireflies I remember from home back East. But these guys don’t fly. Rather they move more like a caterpillar.

  36. Russell Iverson says:

    I just found some glow worms/bugs at 9200-9400 feet on Pikes Peak last week. It was like a larve. Kinda squishy when I touched it. It never changed brightness after I touched it. Bigger than a BB but smaller than a pea. Groups of 4-8 in areas of 15ft circumference. on nothing but granite. What the heck are these??? Never seen them in 20 + years on the peak. Please help!

  37. Rebecca L Gray says:

    Saw them in Lake George at 8500 ft on June 23, 2019. They look like larva. Very little ability to move around. I was thrilled. I missed the Kansas fire flies of my chilhood. Glad to see them in CO, but would love to identify them. No legs or antenna. 1/4 “.

  38. Jack Slagle says:

    We had three appear immediately following a rain shower from under the river rocks that are in our yard. It has been over 3 years I believe since there was one that made an appearance. Hopefully they are multiplying under the river rocks.

  39. Cathy Frey says:

    Observed three in the same spot as last year (Santa Fe/Tseuque, NM) exactly the same time – first two weeks in July. Moving around to a different location each day.

  40. Jacob says:

    I live in evergreen CO at 8600 ft. I have five of the same on my property. They are absolutely amazing and I’ve never seen anything like it CO in all my years. Born and raised in the mountains.

  41. Jeremy says:

    I just saw several last night outside of Snowmass Village, at about 9,000 feet. It was on a trail I’ve hiked regularly for years, but I’ve never seen or noticed them before.

  42. James says:

    I just saw one of something very similar looking in Park County, Colorado, at around 9300 feet.

  43. James says:

    Adding to my previous reply from yesterday…
    Looking at my pictures, the one I found appears to be a bit lighter in color than the pic above (though they were taken during the day.. I couldn’t get a night pic)

    I also wanted to mention that it did not blink its ‘light’, but was able to control the brightness (or turn it off).
    The actual light organ appeared to be on the bottom of the last segment, although glow from it could be seen from the top in both of the last 2.

    This is the first time I’ve ever come across any ‘lighted’ bug!

  44. Deb says:

    We live at 6200 feet between wetmore and Florence Colorado. There is a glow worm in our yard tonight.
    Years ago, before the 2000s, we saw them a few times up here but that was before was such a drought.
    Thank you for having and maintaining site. It is excellent!

    • Winnie Flanagan says:

      I am also seeing these in my yard (south of Cañon City CO)for the first time in 16 years. There are 3 that glow shortly after sunset and move short distances each day around rock garden, ground cover.

  45. Jeff says:

    We live at 9300 ft elevation near Bishop’s Castle and started seeing the little worm like bugs tonight.
    Curious to whether these are a firefly larvae or an actual type of glow worm.
    Can anyone clarify?

Leave a Reply

Your email address will not be published. Required fields are marked *