Glowworm: All You Need to Know – A Quick and Engaging Guide

Glowworms are fascinating creatures known for their unique bioluminescent abilities. Belonging to the beetle families Phengodidae and Lampyridae, these insects emit a soft glow that has captured the attention and curiosity of people all over the world. Found across various continents, they have diverse habits and ways of life.

Generally, glowworms can be found in dark, damp habitats like caves, forests, and under logs. The bioluminescent glow is primarily used to attract prey and mates. For example, in the Arachnocampa genus, the glowworms use their light to lure small insects towards their sticky fishing lines. On the other hand, in the Lampyridae family, also known as fireflies or lightning bugs, the glow serves as a mating signal between males and females.

But what exactly makes glowworms glow? The secret lies in a chemical reaction within their bodies called bioluminescence. This involves an enzyme called luciferase that reacts with a compound named luciferin to produce light without generating heat. This unique ability not only makes glowworms an object of wonder but also an inspiration for scientific research in areas like medical imaging.

In summary, this article serves as your go-to guide for all things glowworm-related.

What Are Glowworms

Meaning and Bioluminescence

Glowworms, also known as glow worms, are bioluminescent creatures that produce light through a chemical reaction in their bodies. Some glowworms refer to fly larvae, like the ones found in the Waitomo Cave in New Zealand, while others belong to the beetle families Phengodidae and Lampyridae¹². This trait of glowing helps them in various aspects of their lives.

Examples of Glowworms

• Waitomo Cave glowworms (fly larvae)
• Phengodidae and Lampyridae beetles³

Characteristics of Bioluminescence in Glowworms

• Continuous greenish-yellow glow
• Visible in larval, female adult, egg, and pupal stages⁴

Prey and Survival

Glowworms rely on their bioluminescence to attract prey and ensure their survival. For example, the Waitomo Cave glowworms use their glowing to lure insects, which get trapped in their mucous threads and are eventually consumed⁵. The glowworm’s large and functional eyes enable them to detect prey over a wide range of wavelengths, from UV to green⁶.

Prey Detection Methods

• Mechano-reception
• Chemo-reception⁷

Glowworms and their bioluminescence thus play a crucial role in their unique survival tactics and fascinating life cycles.

Famous Glowworm Locations

Waitomo Glowworm Caves

Located in New Zealand, the Waitomo Glowworm Caves are one of the most famous glowworm habitats. These caves are:

• Situated near Auckland
• Open for public viewing

The Waitomo caves are home to Arachnocampa luminosa glowworms, which are unique to New Zealand. These glowworms:

• Are born as larvae in nests of about 100 per birth
• Grow up to the size of a mosquito
• Produce bioluminescence through a chemical reaction involving an enzyme called Luciferin

Visitors can enjoy guided tours through the caves to witness the fascinating glowworm displays.

Te Anau Glowworm Caves

Another popular glowworm location is the Te Anau Glowworm Caves. These caves are:

• Located near Lake Te Anau
• Easily accessible through guided tours

Similar to the Waitomo Glowworm Caves, the Te Anau caves are also inhabited by Arachnocampa luminosa glowworms. In addition to their spectacular glowworm displays, the Te Anau Glowworm Caves also offer:

• Stunning limestone formations
• Beautiful underground waterfalls

Here is a comparison table of the two famous glowworm locations:

Visiting either the Waitomo or Te Anau Glowworm caves offers an unforgettable experience of witnessing one of nature’s most mesmerizing light shows.

Formation and Features of Glowworm Caves

Stalactites and Stalagmites

Glowworm caves are known for their unique formations, including the iconic stalactites and stalagmites. These cave features form as water with dissolved minerals drip from the ceiling (stalactites) and build up on the ground (stalagmites). Some examples of cave formations include:

• Stalactites: Hang from the ceiling, resembling icicles
• Stalagmites: Grow upwards from the ground, appearing as conical structures

Formation Process

The process of forming a glowworm cave starts when rainwater, combined with carbon dioxide, creates a weak acid. This acidic water seeps into the limestone bedrock below and dissolves the rock, gradually creating the cave. With time, the cave becomes a favorable environment for glowworms to inhabit.

Water Flows and Unique Cave Environment

Water flow plays an essential role in glowworm caves, providing a consistent environment for the glowworms to thrive. The constant movement of water helps maintain the cave’s temperature and humidity, allowing the glowworms to efficiently feed on small insects carried by water currents.

Visiting Glowworm Caves

Tour Options and Experiences

• Black water rafting: An adventurous experience that combines cave exploration with rafting in underground rivers, lit by glowworms.
• Small boat tours: An easy and relaxing way to explore the glowworm caves and enjoy the sight of the bioluminescent worms hanging from the ceiling.
• Guided walking tours: Led by knowledgeable guides, these tours may include stairs and ladders for a close-up view of the worms and the cave formations.

Note: Most tours are family-friendly and safe for children.

Best Time of Year and Attractions

• April to October: An ideal time to visit the caves since the glowworms are more abundant during these months.
• Waitomo Glowworm Cave: A must-visit attraction in New Zealand, located near the Waitomo Caves village, around 202 km south of Auckland.

Comparison Table:

Guides and Safety Precautions

• Guides: Knowledgeable, friendly, and safety-conscious guides will help you make the most of your visit.
• Safety: Wear appropriate clothing (layers and waterproof gear), follow the guides’ instructions, and stay on the designated paths.

Remember to always respect the sensitive cave environment.

Capturing the Beauty

Glowworms provide a unique and mesmerizing sight, which many photographers are eager to capture. This section will guide you through some tips and tricks for photographing these fascinating creatures, as well as notable photos that have captured their beauty.

Photography Tips and Tricks

• Camera settings: To photograph the bioluminescence of glowworms, use a camera with manual settings. Set a long exposure time (15-30 seconds), a high ISO (800-3200), and a wide aperture (f/2.8-f/5.6).

• Tripod: Use a sturdy tripod to eliminate camera shake during long exposures.

• Lighting: Refrain from using flash or external lighting, as it can disrupt the glowworms’ natural behavior.

• Location: Look for glowworm habitats, like caves or forests, and visit during a new moon or overcast night for optimal darkness and visibility.

• Patience: Capturing glowworms may require time and multiple shots to achieve the desired effects. Adjusting camera settings and experimenting with angles can improve your results.

Notable Photos

1. Glowworm Cathedral, Waitomo Caves: An iconic photo showcasing the enchanting display of glowworms in New Zealand’s famous Waitomo Caves.

2. Glowworm Constellation, Huhu Cave:: This striking image captures the surreal, starry-sky effect created by glowworms in Huhu Cave, New Zealand.

With these tips and inspiration, you’ll be well-equipped to capture the magic of glowworms in your photography efforts.

Visitor Reviews and Experiences

Unique and Memorable Encounters

Glowworms offer a truly magical experience for visitors. People are often captivated by the serene beauty of the bioluminescent creatures, especially when visiting renowned locations like Waitomo Glowworm Caves in New Zealand. One visitor described the atmosphere as feeling like being in a “glittering, star-lit universe,” while another shared that the fascinating glowing displays left them in awe.

Examples of unique experiences:

• Witnessing a “living constellation” of glowworms in a dark cave
• Watching the glowworms light up surrounding plants and trees during a nighttime walk on the beach

Disappointing Experiences

Although many have unforgettable experiences with glowworms, some visitors express disappointment. Reasons for negative reviews typically stem from unmet expectations or environmental conditions affecting the viewing experience. For instance, some people might not find the glowworms’ light as bright or as numerous as they envisioned. Additionally, weather conditions, such as heavy rainfall or strong winds, may result in fewer glowworms being visible.

Comparison table of unique and disappointing experiences:

Remember, even if some people have disappointing encounters, the majority of visitors come away with fond memories and a renewed appreciation for the wonders of nature.

History and Significance

Glowworms have intrigued humans for centuries. They hold a unique place in various cultures and folklore due to their bioluminescent properties. Their bioluminescence serves multiple purposes, including attracting prey and signaling potential mates.

One notable species of glowworms is the Phengodes, found in North and Central America. In some cases, a single Phengodes female can lay up to 53 eggs. Glowworm larvae are cylindrical with short legs, and their length varies from 15 to 65mm.

The fascinating phenomenon of glowing creatures has captured attention in literature, art, and music. The significance of glowworms and fireflies in Western culture was explored in a research paper, which highlights their symbolic role as symbols of light and hope.

Glowworm characteristics:

• Bioluminescent
• Larvae are vermiform
• Cylindrical body with short legs
• Antennae are three-segmented
• Size ranges from 15 to 65mm

Despite their fascinating nature, glowworms should be observed with caution. Protecting their habitats and allowing them to thrive in natural ecosystems is essential for maintaining a healthy balance in the environment.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Pink Glowworms in Southern California

Glow Worms!
I was walking through my front yard in the Santa Monica Mountains in Southern California last night and wondered why there was a glowing LED on the ground. Upon closer inspection I found two glow worms. One blinked out right away upon being disturbed, but the other kept right on glowing. I’ve lived in California for 33 years and have never seen any bioluminescence. This was an exciting first. Just thought I would share my find. All the best,
Sean

Hi Sean,
Though your image is a bit blurry, it is wonderful to see the glow as well as the Glowworms.

Update:  September 14, 2013  (From our personal email account)
Hello Daniel:
Hope all is well these last few days of summer….
Here’s a puzzle:  A colleague of mine said his coworker observed a firefly for an hour last night in his Woodland Hills backyard. Is that possible? Fireflies? I think of them as more midwestern…what could this have been?
Any thought would be appreciated…
Best,
Brenda Rees
Editor
Southern California Wildlife

Hi Brenda,
Thursday and Friday are very long work days for me.  Sorry for the delay.
This one has a confusing answer, and you didn’t explain exactly what the person saw.
We have several species in the Firefly family Lampyridae, but they are not bioluminescent.  To further confuse things, one has the common name California Glowworm, but Glowworms are in a different family.
2013/09/06/california-glowworm-2/
http://bugguide.net/node/view/251917
We have Glowworms in the family Phengodidae as well.  They glow as larvae, and females are larviform are are supposed to glow.  Winged males do not
2013/09/02/glowworm-13/
http://bugguide.net/node/view/9382
Hope that helps.  Would be nice to know exactly what the person saw.  If on the ground and glowing, I’m thinking Western Glowworm.
Daniel

Hi Again Brenda,
We have been trying to clean up our California Glowworm and Firefly postings thanks to your email, because there were some inconsistencies.  We found this posting in our archives and it seems like a good place to add your email query.  Though it is commonly called a Pink Glowworm (according to Hogue in the Insects of the Los Angeles Basin), members of the genus Microphotus are actually Fireflies in the family Lampyridae.  Though blurry, this image from our archives shows a nicely glowing individual.  Here is what Hogue writes:  “… the female of the Pink Glowworm … communicates her location to the male … by emitting a continuous uniform luminescent glow.  The adult male has the usual firefly beetle form, but the female is ‘larviform’ (wingless and elongate like the larva …).  The males are not seen as often as the females because they give light only when disturbed, and the light is weak and not used in communication.  The female is fairly common in late spring to early summer in the foothill canyons (a colony was reported from Griffith Park near the Greek Theater, in 1989).  Found at night by its glow and in the daytime under stones lying on leaf mold in grassy areas, the adult Pink Glowworm is easily recognized by the pink color of the flattened segments;  the terminal segments are yellowish.  The segments of the larvae of both male and female are blackish with pink margins.”  See BugGuide for additional information.

Letter 2 – Possibly Caterpillar found in toilet

Subject: Can you tell me about this insect?
Location: La Crescenta, California
July 29, 2012 6:58 pm
Hi!
My daughter found this insect floating in the toilet bowl after a large BM. She was understandably agitated about this, thinking she had passed this out of her body, although this struck her mom and I as highly unlikely. Upon removing it, I found no signs of any fecal matter sticking to it, again suggesting the unlikely possibility of it coming out of her. SAdly, all our internet attempts to idenify this bug accurately have failed. Can you please help? Thanks so much!
Signature: Evan (Ed. Note:  surname withheld for discretionary reasons)

Hi Evan,
Your photos are so blurry a positive identification on our part is highly unlikely, however, we believe based on the coloration and general shape that this might be the larva of a Pink Glowworm, Microphotus angustus, which you can see in better detail on BugGuide.  We hope we are correct and that you can show the online images to your daughter to alleviate her agitation.  Though it is called a Pink Glowworm, this species is actually a Firefly in the family Lampyridae.  The real mystery is how it ended up in the toilet.

Dear Daniel:
A million thanks for getting back to me! Yes, I’m sorry for the blurriness of the photos, I was shooting with an iphone through a plastic bag! The insect has roughly 12 segments, each with bilateral legs, and each segment is pinkish with small white dots, and a visible thin whitish line separating each segment. There is a blue/purple line running along the entire length, visible in these new photos I’m sending you. Its underbelly is completely beige, and there is sparse hair growing especially at the ends. The tail is small and split. My wife tells me that as we live in Los Angeles, CA, we don’t have fireflies here. Could this still be a pink glowworm larva then? Please advise and thanks again for your time, assistance and empathy!
Best always,
Evan

Dear Evan,
Thanks for sending a new photo.  Though the focus is better than the original image, it is still too blurry for a conclusive identification.  This no longer appears to be a Pink Glowworm to us.  Glowworms are flatter in shape and this appears more rounded and the head is wrong for a Glowworm.  It now appears to be some type of Caterpillar, but we cannot determine which caterpillar.  There are Fireflies in Los Angeles, including the Pink Glowworm, Microphotus angustus.  This BugGuide image is from San Diego.  The larvae and the larviform females in the genus are found in several states in the Southwest, according to BugGuide which has this distribution map.  We believe Glowworms are most commonly found in the foothills and your La Crescenta location supported that wrong guess.

Dear WTBers!!
You guys are truly da bomb! Thanks so much for your generous and helpful assist with this mystery!  Luckily, the caterpillar (both my wife’s initial guess and mine!) has survived its detainment, and has been released back into the wild no worse for wear (and hopefully, with a bit more caution when dealing with small bodies of water!) Thanks again for providing such quick and valuable service; we’ll be sending our contribution to keep you all afloat for future mystery solving.
Best always,
Evan

Letter 3 – Glowworms or Christmas Tree Lights???

Subject: Glowworm Colorado
Location: Grand Junction, Colorado
April 20, 2015 8:20 pm
Hi! I just moved to Grand Junction, CO. We were enjoying a BBQ and noticed our neighbor’s tree is glowing. I am going to head over there tomorrow to see if I can find the cause.
Signature: Kat

Dear Kat,
We can’t help but to wonder if recent changes in the status of controlled substances in Colorado have in any way affected your perception of reality and the world around you.  Have you entertained that these might be Christmas Tree lights and not glowing Glowworms?

Letter 4 – Western Banded Glowworm

Very strange bug
March 11, 2010
This bug has an exo-type skeleton, is centipede like, but only has legs towards the front of its body – looks like six. It rolls up when scared. It’s black with beigeish- yellow in between segments. It’s segmented like a critter from the sea.
Gualala Ridge Farms
Gualala, Northern California Coast

Dear Gualala Ridge Farms,
We believe this is the first letter we have ever received from a piece of real estate.  This is a larviform female Western Banded Glowworm, or perhaps it is an immature larva.  The species is sexually dimorphic, which means that the winged males look nothing like the females which resemble larvae.  When we posted a photo of a female Western Banded Glowworm in 2004, Eric Eaton wrote in the following comment:
“Dear Daniel:
Whoah! Tell him to turn out the lights and he’ll get a real surprise:-) That sure looks like a larviform female of the glowworm, Zarhipis integripennis. In fact, I think we still need a shot of this for our field guide…. They feed exclusively on millipedes, so he could conceivably keep her in a terrarium with some soil and leaf litter and add a millipede or two….He could also take her outside some evening and see if she attracts any males (which ARE beetle-like, fly, and have these amazing feathery antennae). She will glow bright greenish-yellow from the pale membranes between her segments. Thanks for sharing! Makes my day:-)
Happy holidays to you.
Sincerely,
Eric”

Dear Daniel,
Thank you for the response.  My son, Dylan, who is 7, is thrilled to know we have glow worms on our property.  The next one we find, we will try the millipede experiment.  It is pouring rain today so we let her go where we found her.  I know Dylan will be gathering millipedes in soil until we find the next glow worm.  As soon as he read your email he turned off all of the lights in the house, but we did not see a glow, so we decided to let her go.
Thanks again for your website and your response.  Young bugologists such as my 2 kids love looking up bugs on your site when we find them.
Cindy

Thanks for the followup Cindy.  The Featured Creatures website also has some great information.

Letter 5 – Could Glowing Larva be Wireworm???

Subject: Glow worm?
Location: Rimrock, AZ
April 25, 2017 8:27 pm
Found this on the floor of my apartment tonight. What is it?
Signature: Laura

Dear Laura,
This does not look like a typical Glowworm to us.  Glowworms or Railroad Worms are the larvae of beetles in the family Phengodidae.  This doesn’t look like a Firefly Larva from the family Lampyridae either.  It does look like a Wireworm, the larva of a Click Beetle.  There are bioluminescent Glowing Click Beetles in the genus Deilelater, but we have not been able to locate an image of the larva.  BugGuide only lists North American sightings in Texas and Florida, however, BugGuide does indicate “D. physoderus GA-FL-AZ, Mexico.”  Though that is circumstantial, our best guess right now is that this might be the larva of a Glowing Click Beetle.

Letter 6 – Glowing Fire Beetle from Puerto Rico

Subject: 1 in wbeetle with glowing eyes
Location: Puerto Rico
April 16, 2017 2:22 am
Saw this beetle in Puerto Rico- glow in the dark eyes like lightening bug color and about 1 inch long
Signature: Katie darrow

Dear Katie,
Based on some research we did many years ago, we learned that Fire Beetles in the genus Pyrophorus are sometimes called Cucujos.  What you have mistaken for glowing eyes are in fact just eyespots.  The Fire Beetle’s true eyes do not glow.

Letter 7 – Glowworm Larva or Railroad Worm

Black with orange spot… not a centipede
Sun, Mar 22, 2009 at 6:11 PM
Hi I found this interesting specimen in George Washington national park located in Staunton Virginia. I have never seen anything like it and have been camping there for about ten years. I was hoping you would be able to ID it for me as it’s a very interesting and colorful insect. I thank you for your time and effort… I love your site and have used it extensively to satisfy my curiosity about bugs…
Thanks!!
David Barton
Staunton Virginia

Dear David,
What a positively magnificent Glowworm Larva you have photographed. it is in the family Phengodidae. There is an identical specimen posted on BugGuide that was photographed in North Carolina. It is unfortunate that you didn’t have the opportunity to see it glowing a luminescent green in the dark.  Glowworms are also known as Railroad Worms.

Letter 8 – Glowworm Glowing!!!

Glow worm found in SE Wisconsin
Hi, I found your web site while looking for an answer to my question. I found this little booger in the grassy field in my back yard. I live in North Prairie Wisconsin, USA. Thanks,
Greg McLain

Thanks Greg,
Now our readers can see what a Glowworm looks like when it is glowing.

Letter 9 – Western Banded Glowworm

what is this creature?
Hello,
I live in San Jose, Ca. I live between open space and County parks in the mountains. I took this picture of a ????? Some type of myriapod, or larvae??? Can you help me identify it? I have only seen this one, and it appeared to be trying to eat a dead Millipedede. I had a hard “shell” and two legs together. Thank you,
Aaron

Hi Aaron,
This beauty is a Glowworm Larva in the family Phengodidae. Interestingly, there is an image on BugGuide of a Glowworm eating a Millipede.  This might be a Western Banded Glowworm, Zarhipis integripennis.

Letter 10 – Female Pink Glowworm

Subject: Pink Glow Work
Location: Lake Lopez, California
May 11, 2015 1:34 pm
We found this worm at Lake Lopez this weekend on an Oak Tree. Very fascinating!
Signature: DiAnn

Dear DiAnn,
We believe your female Pink Glowworm (actually a Firefly) is Microphotus angustus, which is pictured on BugGuide, though there is a dearth of information on the site.  Luckily our favorite text for local species in our area, The Insects of the Los Angeles Basin by Charles L. Hogue, provides a wealth of information:  “the female of the Pink glowworm (which is 1/2 in.,or 13 mm, long) communicates her location to the male (1/4 in., or 6 mm, long) by emitting a continuous uniform luminescent glow.  The adult male has the usual firefly beetle form, but the female is ‘larviform’ (wingless and elongate like the larva …).  The males are not seen as often as the females because they give light only when disturbed, and the light is weak and not used in communication.  The female is fairly common in late spring to early summer in the foothill canyons  … .  Found at night by its glow and in the daytime under stones lying on the leaf mold in grassy areas, the adult Pink Glowworm is easily recognized by the pink color of the flattened segments;  the terminal segments are yellowish.  The segments of the larvae of both male and female are blackish with pink margins.”  We are very excited to include and to feature your Pink Glowworm documentation.

Letter 11 – Glowworm

colorful larva with red spots
Location:  southern part of North Carolina
September 24, 2010 7:32 am
This approximately 2-inch-long larva was found crawling in the bathroom of a home in the southern part of North Carolina on September 23rd. Thank you for helping us identify it!
Signature:  impressed by biodiversity

Dear Impressed,
You may have been even more impressed had you turned off the lights and watched this Glowworm do what it is best known for, glowing in the dark.

Thank you!  It does glow!  The glow is very faint, but it is there!  Amazing!!

Glowworm Update:  Glowing and Food Chain
September 27, 2010
Dear Daniel,
My sister recently sent in a photo of a larva that my daughter found in the bathroom:
Well, we immediately checked to see if it was glowing and it was – very faintly. We then learned that she (yes, it’s a girl glow worm!) should like millipedes and we wondered if she would glow more if she regained her strength.  My husband graciously found a small millipede for her for a bedtime snack.  She loved it! It was nothing but a pile of shell/rings in the morning.  Next we found a BIG millipede.  Within an hour the millipede was immobilized and over the past two days the glow worm has been tunneling inside the millipede eating everything but the shell.  It is quite gruesome – but fascinating! Anyway, we noticed last night that she seemed to be glowing more – while her head was in the millipede!  We pulled her out, but by the time we figured out camera settings, her glow faded.  Now, I am happy to announce, that I successfully captured a bit more of her glow this afternoon!  Attached are two photos: one of her eating and the other of her glowing.
Thank you for your help.
Awed by God’s creation,
Sherry Lorei

Dear Sherry,
Thank you ever so much for taking the time to send these awesome photos.  Though we have other images in our archives of Glowworms glowing, this is the first Food Chain image we have of the remarkable feeding habits of this amazing creature.

Letter 12 – Male Glowworm

Male Sawfly – family argidae?
Location: Naperville, IL
June 24, 2011 6:27 pm
Hi Daniel~
I have searched and searched, and the best I can do at ID-ing this inch-long insect on my house siding is to conclude that it is some kind of male sawfly, per its wasp-like appearance and its intensely-feathered antennae. I’ve looked at conifer sawflies and argid sawflies, but the length of its body with respect to its wings is throwing me off – as is its impressive set of mandibles and armor between its wings and head. So perhaps it’s not a sawfly at all? Can you help? Thanks so much! (P.S. You asked a question a few days ago regarding two photos I sent of hatching Monarch caterpillars. The only way I was able to respond was via a comment to those photos, not in the usual way. I hope you saw my reply.)
Signature: Dori Eldridge

Dear Daniel~
I found it!  It’s not a sawfly at all.  It’s an adult male glowworm beetle – probably a Phengodes plumosa.  Those elytra and the length of its body sent me to beetles after I exhausted the sawfly and ichneumon wasp categories. There is an image on bugguide.net that is nearly identical to mine: http://bugguide.net/node/view/167293/bgimage.  Still, you might like to add these photos to your glowworm collection.  Thanks so very much!
Dori Eldridge

Hi Dori,
We are happy that you were able to self identify your male Glowworm, and we are thrilled that we can post your photos, though we disagree with your comment that the photo on BugGuide is nearly identical to your photo.  The color and clarity of your image are even better.  It is interesting that the antennae are plumose and the species name of Phengodes plumosa acknowledges that.  Your photos are awesome.

Yes!  …especially considering that it is only the adult male glowworms that have the plumose antennae.  I feel especially lucky to have spotted and photographed this insect now after reading that they’re not so commonly encountered.  It posed for me without moving for about 3 or 4 minutes, after which I left it.  When I returned a few minutes later, it had gone.  I hope to find a female larviform glowworm one day to photograph, too.  Thank you for your most kind words, and best regards to you.  -Dori

Letter 13 – Glowworm

Hi,
I have a question. What is he and what do I feed him? I found him in
my back yard in Iron Station, NC. He was in the grass by a water
spicket. A mowed yard surrounded by several 100 inhabited woods. I
live in the country. He is very active in late day, night and seems to
be eating grass. His glowing is bright and is 24 hours a day. He is
very beautiful. I would like to know what to feed him so I don’t hurt
him. I am keeping him in a aquarium.
He is slightly fleshy segmented and seems to fold within himself but not
as much as a grub worm or as thin as a centipede. He is around 2.2
inches long when open all the way up and with around 12 segments. His
head is dark gold, triangle shaped with several short antenna and tiny
pinchers. He is very active and glows beautiful neon green in between
each segment and on his side is very bright glowing dots below each neon
strip. Gorgeous when he moves. Absolutely reflects on the grass around
him.
Is it a larva or a worm?
Thanks for your help in identifying him. I think he is unique.
Thank you.
Ivy Baker

We are currently trying to help Ivy identify her beetle grub.

Update:  May 12, 2014
This posting is over ten years old, and in that time, we have gotten much better at identifying the myriad creatures sent to us for identification.  We just received a comment indicating that Michael saw an individual glowing.  Despite two comments identifying this as a Glowworm, we never really updated the actual posting, so we are remedying that now.

Letter 14 – Glowworm

Crazy mystery scorpion/worm thing?
May 27, 2010
I vacuumed this out of the bottom of our pool in the piedmont of North Carolina. Its got a hard jointed shell, 6 legs, and what looks like a pincher or feeler on the end of its tail. Curled when found dead but would probably measure 3.5″ long when flat. What is this!?
Sarah in NC
Iredell County, North Carolina

Hi Sarah,
If it was alive, and if you observed it at night, you would find that this Glowworm was bioluminescent.

Its a real live glow worm??

Sorry my first email was so pointed but I grew up with the stuffed play glow worms and never thought they were real. We’re lovers of nature and life of all kinds but we’d never seen anything like this!

Hi Again Sarah,
We are not trying to yank your chain.  This is a Glowworm in the genus Phengodes.  You may verify this on BugGuide.  It is a larva.  Unlike Fireflies which glow as adults, with the Glowworms, it is the larvae and the larviform females that are bioluminescent and emit light.  According to BugGuide:  “Phengodid adult females and larvae feed on millipedes” and this poor Glowworm must have fallen into the pool during its nocturnal hunting. Glowworms are also known as Railroad Worms, and we once received an awesome photo of a glowing Glowworm.

Letter 15 – Railroad Worm

Subject: Beautiful Centepede/Millipede
Location: Jordan Lake/ Chapel Hill, NC
April 18, 2015 9:29 pm
Tonight I came across this photo from a couple of years ago. At the start of fall, I pulled a blanket out of a plastic storage container. When I opened it up this bug fell out. It was about 5 inches long. It’s beautiful but I didn’t dare touch it! I grabbed a container from the trash and scooped up the bug, took a quick pic and tossed it outside. I’ve been wondering what it was ever since!
Signature: Frightened of Beauty

Dear Frightened of Beauty,
This is a Railroad Worm, the larva of a Glowworm Beetle in the family Phengodidae and probably in the genus Phengodes because of its similarity to this image posted on BugGuide.  As the name indicates, these larvae are bioluminescent, and had you had the opportunity to view this Railroad Worm in the dark, you would have been treated to a light show.

Letter 16 – Glowworm

Subject: What is this larva thing?
Location: Carmel Valley, CA
September 2, 2013 12:16 pm
This millipede looking larva thing was hiding under a bag in our house. Help? Light brown body with dark brown segments six legs in front of body. Little over an inch long.
Signature: Curious in Carmel, CA

Dear Curious in Carmel, CA,
If you take your critter, the larva of a beetle in the family Phengodidae, into a darkened room, you will see why it earned the common name Glowworm.  We believe it is a Western Banded Glowworm, Zarhipis integripennis, and you can find more information on Bugguide.

Letter 17 – Adult Male Glowworm

Subject: whats this?
Location: middle georgia
July 31, 2012 12:38 pm
Hi, I recently found this bug in my home. I live in middle Georgia and found this bug last month (June 2012). At first I thought it was a spider because it looked as though it was slowly dropping from the ceiling like a spider. Then it started flying almost like it was trying to attack us. Usually we’re catch and release any animals but this one was relentless. It attacked the ruler we tried to use to scoop it up with…left small holes in it. I’ve looked everywhere trying to find out what it is so any information would be great. It’s the only one I’ve ever seen so far. Thanks again.
Have a great day
Tj Alligood
Signature: Tj Alligood

Hi Tj,
This fascinating creature is an adult male Glowworm Beetle.  The larval Glowworms, sometimes called Railroad Worms, are amazing creatures that are capable of bioluminescence.  Females are wingless and resemble the larvae.

Mystery solved…Thank you so much! Your site is great! Have a great day!
Tj

Letter 18 – Glowworm Larva

What’s this Bug?
Location: Tehachapi, California (about 35 miles East Southeast of Bakersfield). The elevation there is about 3900ft.
May 17, 2011 3:23 pm
Hello, a friend recently (today) found this crawling across her floor at her home in Tehachapi, California (about 35 miles East Southeast of Bakersfield). The elevation there is about 3900ft.
It’s about 2.5in long.
We’ve ruled out millipede and centipede due to the inconsistency of the legs per segment. She assures me there were more legs than the 3 pair that can be seen in the photo. I’m thinking it’s in it’s larval or pupal stage.
What do you think?
Signature: with love? I don’t know what you mean by this.

This sure looks like a Western Banded Glowworm to us and you are correct that it is a larva.  Here is a photo on BugGuide that is very similar.

Daniel,
I’m impressed!
I’ve been reading up on your findings and I concur with your ID.  I was leaning towards some form of Coleoptera from Lepidoptera (just didn’t feel very moth-like).  I knew those Entomology classes in college would help out some day.
Thank you very much for helping out.
Sincerely,
Mark
Mark Meredith
Field Botanist, Graphic Designer

Letter 19 – Beetle Larva from South Africa

Subject: unknown bug
Location: Pietermaritzburg, South AFrica
July 10, 2015 12:56 am
hi Bugman
found this critter roaming around my house.
no idea what i’m looking at.
Signature: werner

Dear Werner,
This is some species of beetle larva, probably either a Firefly or a Netwing Beetle.  It is very difficult to distinguish the family from the very similar looking larvae.   There is a similar looking image posted to iSpot.

Daniel thank you so much for the mail.
You made my day and my whole family’s!
We’ve been sending the video on all day.
The most amazing part is i own a company called Firefly in South Africa!
I love finding new bugs to identify but never came across one of them before.
I will research their life cycles tonight.
Thanks again and we will happily donate to your site.
Werner van der Westhuizen
The Firefly Golf Company

Letter 20 – Bioluminescence in Venezuela

Subject: Iridovirus?
Location: Venezuela
April 26, 2013 9:02 pm
Hi, I had never seen a lighted grub, so I searched on the web and found something about iridoviruses? Is this the case? Or it is a firefly grub? This pic was taken in south america (Venezuela).
Signature: Javier P.

Dear Javier,
We are not familiar enough with the bioluminescence patterns of South American creatures to determine the identity of the creature you saw.  Larvae and adults of many Glowworms and Fireflies have bioluminescence.  You can begin by searching for information on the Bioluminescent Beetles website.  The only references in our archive on Iridovirus pertain to Sow Bugs turning a blue color, and there is nothing about them glowing.

Letter 21 – Glowworm Glowing

Another glowing bug (not a firefly larvae to my knowledge)
To whom it may concern, I am enclosing two pictures of the same larvae; one with lights on and one with lights off. I am clueless and every search I come up with leads me to fireflies. If the pictures do not come through for you I will post them in cyberspace and send yo the links. Sorry, I cropped a photo down.
Sincerely
Bob Dodd
http://www.bugpeople.org/taxa/Coleoptera/Phengodidae/FamilyPhengodidaePage.htm
It turns into a beetle and the male has huge antennae.

Good Going Bob. We are happy to post your image of a Glowworm.

Letter 22 – Giant Glowworm

red spotted 3 inch long black beetle larvae
Dear Bug people,
I loved looking through your site…but I couldn’t find my beetle larvae…seems bug net doesn’t have the category either. I looked through all of your beetle pages. We found this guy on top of the pine straw in a natural area in our yard in North Carolina (september). It was 2.5 to 3 inches long. Please help us identify it. Last week we discovered the arrow headed flatworm in our yard and used your site to identify it. Thanks so much,
Peri Buus

Hi Peri,
We suspect if you viewed your Giant Glowworm in the dark, you would be treated to some bioluminescence. We did locate a near identical larva on BugGuide where it is listed as either genus Zarhipis or Phengodes.

Letter 23 – Glowworm

Glow in the dark larvae?
My backyard is riddled with these.
Either the house is built on a superfund site or….?Notes: Where found: Spring Green, WI Date: June 14th Heavily shaded areas, rich soil. Thanks for the great website and your help!
Rob Greenleaf

Hi Rob,
What a wonderful photo of a glowing Glowworm, the larval form of a beetle.

Letter 24 – Glowworm

A lovely Larva
Hey Bug Man:
Found this larva tonight by the edge of the driveway partially hidden by vegetation. Upon closer inspection I realized it was a firefly still in the larva stage as I could see the bioluminescence. I took it inside and made a thirty second time exposure with the camera mounted on a small table top tripod. Voila! The inset picture is the appearance under normal room light with the smaller end being the head. I realeased it back outside under some heavier vegetation so that hopefully in another month or so it will soon be flying over all the corn fields here in souther Wisconsin creating a wonderful summer night spectacle. Nature is an endless source of wonder! Thanks for a great website and for all your hard work keeping as such.
m

WOW M!!!,
What a gorgeous image of a glowing Glowworm, probably the best we have ever received. Glowworms are a separate family from Fireflies, Phengodidae as opposed to Lampyridae. Both Glowworms and Fireflies are Beetles.

Letter 25 – Glowworm

winged bug w/feathered antennae
We’re in Portland, Oregon and have never seen this bug before. Although it looks beatle-ish in these photos, the black part are wings. Found it at about 10 p.m. – it was flying toward the light. Can you ID?
Elisa

Hi Elisa,
You are right about this being a beetle. It is an adult male Glowworm in the family Phengodidae.

Letter 26 – Glowworm

GLOW-WORMS
(10/12/2003) Hi
I fancy myself as an amateur entomologist, but I recently found two creatures that have me stumped.  Four times over the course of the last month I found what appears to be a large grub.  I initially thought
the animal was a centipede of some sort, but upon closer inspection it seemed to be an insect.  It had 7 or 8 segments with 6 legs on the second segment.  It trailed its long tail after it with amazing speed.  Each shiny, plated segment had 2 black spots on a background of red/rust and yellow.
Today while walking in a nearby forest (this time with camera in hand) I spotted a bizarre blue grub.  It had the same body plan as the first animal I described: segmented with 6 legs up near the front…except this one was a dazzling iridescent blue.    I was able to snap a couple of nice photos.
I am guessing that these are Coleoptera spp.  larvae.  Am I correct??
Any insight would be greatly appreciated.  This is driving me nuts!
Thanks!
Melody McFarland
Durham NC

Dear Melody,
It appears as though you have photographed the elusive glowworm, either a female or a larva. Glowworms are beetles from the family Phengodidae. It is a small group of relatively uncommon beetles closely related to Lampyridae or Fireflies. Liker the fireflies, glowworms are capable of luminescence, or glowing in the dark. They are usually found in foliage or on the ground. The adult females of many species are wingless and luminescent. They are predaceous. I will try to get additional information on your exact species which is an amazing color. Here is the only photo I could locate online of a pair of glowworms, and as you can see, structurally, the female looks much like yours in everything but color.

Hi Daniel!
Thanks for the prompt reply!  I combed through every insect book I have and was not able to find anything. Your website is fantastic!
thanksagain
Melody

Ed Note:  January 13, 2009
This posting got lost in our site migration and we are just now posting it live again.

Letter 27 – Glowworm

Red, Black and Yellow Centipede Like Insect
July 12, 2009
Hello Bugman. I encountered this centipede like creature while walking on an old blacktop in Central Arkansas just west of Little Rock. I have never seen something like it. Sorry that I could not get a better picture of him. At first he was crawling around free, but when I uncovered it, it curled defensively into a ball and would not stretch back out. Hopefully the distinctive colors will help.
Ben Batten
Little Rock, AR

Hi Ben,
This is actually a beetle larvae known as a Glowworm.  Sadly, you did not get to witness its bioluminescence since your sighting was during the day.  We found a very similar image on BugGuide, but your specimen has even brighter coloration.

Letter 28 – Glowworm

Curled up centipede/millipede with red spots
Location:  Chapel Hill, NC
August 10, 2010 9:56 pm
Hello! I found this bug the other day while on a walk. I put him on a leaf to take a picture, but unfortunately he curled up and wouldn’t uncurl for as long as I waited, so I just set him in the grass. I thought he was rather unusual looking with striking red spots on a black background, and those large segments. He was maybe two inches long or a bit less (it’s hard to measure when he’s curled up).
Vicki

Hi Vicki,
This is the larva of a beetle in the genus Phenogodes (see image on BugGuide), commonly called a Glowworm.  Had you taken encountered it at night, you would have been treated to a nice display of bioluminescence.  We are very excited to have your photos of the defensive position this Glowworm assumes when threatened.

I’m sad that I missed that bioluminescence.  Keep up the good work!

Letter 29 – Glowworm

Caterpillar?
Location: Spring, Texas
June 4, 2011 2:40 pm
Could not identify this through google, so posting here.
6 thoracic legs, no visible abdominal prolegs, about 2-3 inches long.
Signature: Ian

Dear Ian,
Shut off the light and treat yourself to an unusual sight, a glowing Glowworm.

OK I found it, it’s a glow-worm.

Letter 30 – Glowworm

Do you know what kind of bug this is?
Location: Charlotte, NC
October 9, 2011 11:10 pm
Hi there,
This bug was outside my door yesterday. I live in Charlotte, NC. Any idea what it is?
Thanks,
Charlotte
Signature: Charlotte, NC

Hi Charlotte,
Had you turned off the lights, you might have been treated to seeing this Glowworm in the genus Phengodes glow, like this image from our archives.

Thank you so much!  My friends thought it was a palmetto bug egg/larvae, etc.  Whew.  I am relieved!

Young Palmetto Bugs look just like adults, but smaller and without wings.

Letter 31 – Glowworm

Subject: glowing worm
Location: Auburn, NY
August 2, 2014 1:54 pm
I found this worm in my kitchen late at night, maybe brought in on the fur of a cat, but
it was glowing yellow/green, I caught it and looked at it in the day and still don’t know what it is
Signature: Pat P

Hi Pat P,
Though it is commonly called a Glowworm or Railroad Worm, this is actually the larva of a beetle in the family Phengodidae, and we have several images on our sight that document the glowing of Glowworms.

Thanks so much.
I was at a loss to know.
Have a truly wonderful day!
Pat

Letter 32 – Glowworm

Subject: What’s this bug
Location: North America , Georgia
August 6, 2014 9:18 am
I live in middle Georgia (United States) , it’s Summer here I found this strange flying bug last night flying at me but it disappeared. This morning it was in my room. What is it , where did it come from and more important who sent it
Signature: Yes

Dear Yes,
You write as though you suspect this is a conspiracy.  This is an adult male Glowworm Beetle, and the luminescent larvae are sometimes called Railroad Worms.  It is a harmless and beneficial insect.  Since the concept of Spontaneous Generation has been scientifically dispelled, we postulate that it is descended from other Glowworms, and we can’t imagine who sent it, but since “males come to lights” according to BugGuide, we imagine it was attracted to your illuminated interior.

Letter 33 – Glowworm

Subject: Glow worm in Colorado
Location: 38’48’28.8 – 104’53’57.3
June 28, 2015 11:06 pm
The night of June 27 , 2015 22:15 I was returning from a very long hike in the front range of Colorado Springs. As I walked up the the HighiDrive road I noticed what looked like the reflection of the moon light off of a crystal in the granite of a large rock. As I moved the light didn’t go away. Upon closer inspection it was very green in color. I knew it must be chemoluminesance. I grew up in these mountains for over 40 years. I have never seen this here before. It was at 7520ft and there were several of them along 1/2 mile portion of the road. The one in the photo was much brighter then the other ones I saw. The question is what is the life cycle of this insect and what are the limiting factors keeping there numbers down? Photo attached. Thank you.
Signature: Bob Zook

Dear Bob,
Though they are commonly called Pink Glowworms, this member of the genus Microphotus is actually a Firefly in the family Lampyridae, and not a true Glowworm in the family Phengodidae.  There is not much information on BugGuide.  In a 2005 posting on our site, we learned through Eric Eaton who contacted an expert that:  “He notes that they were all females collected in June and July and that, although their identities are not certain, they are probably pecosensis. “  Based on information we have learned through the years, we suspect this is an adult, larviform female.  We have been receiving numerous recent comments to our Pink Glowworm posts regarding new sightings.

Letter 34 – Glowworm

Subject: Long red and black sand beetle larvae?
Location: Chesapeake, md
September 13, 2015 11:07 am
We found this on brownie beach on the Chesapeake bay, maryland. What could it be?
Signature: Divya

Dear Divya,
This is a Glowworm or Railroad Worm.  They really do glow in the dark.
Daniel, thank you so much! Wish I had known to test out the glowing, but it was really hard to google image a replica of long red black beach bug. Anyway, my 4.5 year old loved it:

Letter 35 – Glowworm

Subject: Found in South Florida. What is it?
Location: South Florida
July 8, 2017 6:43 am
this bug was found by a neighbor in South Florida. Any idea what it is? I have never seen anything like it.
Signature: Kim

Dear Kim,
The angle of this image is quite odd, but this is still recognizable as a male Glowworm, which you can verify by comparing your image to  this BugGuide image.

Letter 36 – Glowworm

Subject:  Caterpillar like black bug with red spots
Geographic location of the bug:  North Carolina
Date: 10/25/2017
Time: 09:22 PM EDT
Saw this in the bathroom on the floor at work today. Never saw one before and was curious to see what it was exactly. It appered to only have 6 legs and drag its rear behind. Took the pics and it was relocated outside where it belongs.
How you want your letter signed:  Gin

Dear Gin,
Had you turned out the lights, you would have seen this Glowworm phosphoresce with green light.  A glowing Glowworm, also known as a Railroad Worm, is an impressive sight.

Letter 37 – Glowworm

Subject:  Bioluminescent millipede
Geographic location of the bug:  Wisconsin
Date: 06/28/2018
Time: 11:49 PM EDT
Your letter to the bugman:  Hi,
We live in Wisconsin, USA and found a couple bioluminescent millipedes here at our home. From what we’ve been reading, they’re not native to this area or maybe even this country.
Anywho, we’re now very curious about this creature. Any info would be greatly appreciated.
How you want your letter signed:  Brittany

Dear Brittany,
This is not a bioluminescent Millipede, but rather a native Glowworm.  A Glowworm is the bioluminescent larva of a beetle in the family Phengodidae, a group distinct and separate from Fireflies or Lightning Bugs in the family Lampyridae.  Adult male Glowworm beetles are quite unusual looking in their own right, though they are not bioluminescent. 

Letter 38 – Glowworm

Subject:  Unknown glowing caterpillar
Geographic location of the bug:  Avoca IA
Date: 06/17/2019
Time: 08:41 AM EDT
Your letter to the bugman:  I found this at night, glowing on the ground next to my home.  I live in a rural area.  I have not seen anything wit this glow pattern before or since. It was found June 2 at 10 pm.  I returned to where I found it after photographing it. I am attaching a picture with the lights on so you can see the caterpillar and one with the lights off so you can see its glow.
How you want your letter signed:  Yvonne

Dear Yvonne,
This is a Glowworm, the larva of a Beetle in the family Phengodidae, not a Caterpillar.  Here is a similar looking image from BugGuide that is also from Iowa.

Letter 39 – Glowworm Beetle from Honduras

Subject: Bug from Honduras
Location: Roatan, Honduras
July 28, 2014 9:46 pm
Hello there!
We found this insect in Roatan, Honduras in my friend’s shower. We have spend hours online trying to identify this creature and are coming up empty. The wings on it’s head are so strange! Like long eyelashes! It also looks like the bottom might have a stinger. Please help. We are dying to know the answer.
Signature: Lynette

Hi Lynette,
This is a male Glowworm Beetle in the family Phengodidae, and you can see its resemblance to this image on BugGuide.  The wings and feathered antennae indicate this is a male.  According to BugGuide:  “Adult males have variously shortened/narrowed soft elytra, branched antennae, and bulging eyes; adult females are larviform (often all but impossible to tell from fully-grown larvae) and, like the larvae, have bioluminescent organs.”

Letter 40 – Glowworm Carnage

Subject:  Big flying bug
Geographic location of the bug:  Georgia
Date: 05/02/2019
Time: 09:28 PM EDT
Your letter to the bugman:  This bug was found flying in my room and I have found over 13 total bites from one night. It then turned the entire skin into bumps/rash about 5 inches beside the bite.
How you want your letter signed:  Caitlin jeske

Dear Caitlin,
This harmless male Glowworm is not the cause of your bites, bumps nor rashes.

Letter 41 – Glowworm from Trinidad

Whats this bug called
Location: Trinidad & Tobago, Caribbean
February 3, 2012 7:25 am
My friend found this bug flying around in her kitchen, what is it?
Signature: Betty

Dear Betty,
This is actually a beetle known as a Glowworm.  Adult males fly and have branched or plumose antennae while females are larviform.  Larvae and sometimes females are bioluminescent.  You can compare your photo, which sadly is of a very low resolution, to those posted on BugGuide.

Letter 42 – Glowworm Glowing

Subject:  Banded Glowworm
Geographic location of the bug:  Wyoming, Michigan
Date: 09/18/2018
Time: 10:09 AM EDT
Your letter to the bugman:  Last night I took a video of a Glowworm I found in my garage. I had mowed my lawn previous to finding it and leaf blew some clippings around. I’m assuming that’s how it ended up there. Here are some screenshots from said video. Thanks!
How you want your letter signed:  Aron Adamczyk

Dear Aron,
We believe your Glowworm is in the genus Phengodes based on your location and this BugGuide image.  We were able to increase the highlights in the dark image you submitted which enhances the glow.

Letter 43 – Glowworm, we believe

Subject: Black and Red segmented bug
Location: Roswell NM
July 25, 2012 2:42 pm
I found this in New Mexico, crawling along the ground (July, hot). There are six legs from the first few body segments, and 12 segments in all. The tail has a little hook type protuberance that it uses to walk, and as a prehensile thing when climbing. I’ve never seen anything like it.
Signature: Jason

Hi Jason,
Though we don’t have any individuals with these markings, we are nearly certain that this is the larva of a Glowworm. There is an image on BugGuide of a member of the genus Zarhipis that looks very similar and the genus is reported on BugGuide from nearby Arizona and other western states.

Letter 44 – Glowworm: Zarhipis integripennis

Hiya Bugman,
What’s this critter? Is it a catapede or a millipillar or what? I found it charging across my living room tonight (in bright light). I’ve lived here in Malibu (elevation 250 ft.) for 35 years and have NEVER seen this beast before. I didn’t find him (or her) in Hogue’s Insects of the Los Angeles Basin, nor in some extensive web hunting, so of course I had to bring him (we’ll call him a boy) into the kitchen for a quick photo session. He’s almost 3 inches long in the picture; 4 inches when walking fully extended. Several legs are visible in the photo (top) near his head (left). He’s pale on the underside. I thought he might be a millipede due to his hard, glossy exterior; but he definitely has only one set of legs per section (he has legs along its entire length). And he’s not cylindrical like the black millipedes I sometimes find here, but rather ovoid in cross-section, flattish. But he’s not quite like a caterpillar either; I don’t know any that have such hard bodies… but then look at those horns! In any case, I’m pretty certain he’s not a centipede. So what say thee? If you know this critter, please tell me where he’s indigenous, and if he has a latin name. I have half a hunch that he’s a foreigner in these parts….
Cheers,
Kraig
P.S. If the photo didn’t come through, I can send it as an attachment. I have several other photos as well, if you’d like.

Hi Craig,
I wanted to contact a real expert before writing back to you. Eric Eaton quickly gave this excited reply
“Dear Daniel:
Whoah! Tell him to turn out the lights and he’ll get a real surprise:-) That sure looks like a larviform female of the glowworm, Zarhipis integripennis. In fact, I think we still need a shot of this for our field guide…. They feed exclusively on millipedes, so he could conceivably keep her in a terrarium with some soil and leaf litter and add a millipede or two….He could also take her outside some evening and see if she attracts any males (which ARE beetle-like, fly, and have these amazing feathery antennae). She will glow bright greenish-yellow from the pale membranes between her segments. Thanks for sharing! Makes my day:-)
Happy holidays to you.
Sincerely,
Eric”
So, Craig, I’m sure it would make Eric’s day even more exciting if you would send him a copy of the image for inclusion in the insect guide he is working on. Have a great day.

Letter 45 – Male Glowworm

What’s this bug?
I photographed this insect one night in late May. As for the scale, notice in the first pic, top left corner is a nail head approximately 1/4 inch in diamater. I left the porch light on to attract insects to photograph and this appeared. The photo was taken in Yadkin County, North Carolina. What is it? I really like your site. It’s comforting to know I’m not the only person who likes to photograph bugs. > Tony Hegwood

Hi Tony,
We wanted to verify our conclusion with Eric Eaton. Here is his response: “This is actually a male glowworm, in the genus Phengodes. No wonder he was attracted to light:-) Female phengodids are larviform, meaning they retain all the characteristics of the larval state, but have a fully-developed reproductive system, and compound eyes! They glow between the abdominal membranes. Larval and female phengodids feed exclusively on millipedes. The males are not luminescent. Neat find. A good year for them it would appear, as I’ve seen other images from this season.”

Letter 46 – Male Glowworm

Horntail with furry antennae?
The lighting wasn’t great, but this has black wings and was flying in our house. We’re thinking “horntail,” but can you tell us what kind? We thought it was love bugs (we’re in west central Florida) mating, but it’s just one “love bug colored” flying bug with really big eyes and funny, furry antennae. Thanks so much!
Doug & Alli
New Port Richey, FL

Hi there Doug and Alli,
We thought this was a Fire Colored Beetle, but Eric Eaton corrected us. “The fire-colored beetle is actually an adult male glowworm, probably in the genus Phengodes, family Phengodidae. They do not glow, but the females, which retain a larval appearance even in adulthood, DO glow, with bands that make them resemble caterpillars cloaked in halos of light.”

Letter 47 – Male Glowworm

Subject: red and black bug
Location: wi,usa
May 25, 2015 8:36 pm
Just curious what type of bug things it’s and is it dangerous?
Signature: liz

Dear Liz,
This is a male Glowworm Beetle, probably Phengodes plumosa, and it is perfectly harmless.

Letter 48 – Male Glowworm Beetle

Subject: what is this bug called
Location: Brooksville, florida
January 13, 2013 8:48 pm
Please help my daughter and i identify this cool, crazy looking, flying bug. Thanks
Signature: rylee

Hi rylee,
This is an adult male Glowworm Beetle, probably in the genus Phengodes.  It looks very similar to this individual that was posted to BugGuide.  Larval Glowworms are sometimes called Railroad Worms and they are capable of bioluminescence.

Thank you so very much 🙂

Letter 49 – Male Glowworm Beetle

Subject: Very Interesting Insect
Location: Round Rock, Texas
July 7, 2014 11:58 pm
Hi,
I found this little guy in my house one night and thought it was just another moth or june bug, but once i got close to it I noticed how unusual it was. I have never really seen an insect like this before. I love the antennae on this guy, they’re so intricate. Its very unique looking to me, and I’ve always loved insects. Any information on what this could be would be greatly appreciated.
Thanks!
Signature: – Tyler Moore

Dear Tyler,
Thank you for providing us such marvelous documentary imagery from multiple angles of a male Glowworm Beetle in the family Phengodidae.  Unlike Fireflies, adult male Glowworms are not bioluminescent, however, the larvae, sometimes called Railroad Worms, are capable of emitting light. 

Letter 50 – Male Glowworm Beetle

Subject:  Insects
Geographic location of the bug:  Florida
Date: 08/09/2018
Time: 08:52 AM EDT
Your letter to the bugman:  I found a flying bug in Trenton Florida has wing’s eye lashes Orange and black with a big stinger
How you want your letter signed:  Melissa

Dear Melissa,
This is a male Glowworm, and unlike Fireflies that have bioluminescent adults, it is generally only the larval Glowworms that give off light.  What you have described as “eye lashes” are actually antennae, and there is no stinger.  Glowworms are entirely harmless to humans.  We try to promote tolerance of the lower beasts, and it appears this Glowworm met an untimely death, so we are tagging this posting as Unnecessary Carnage.

Letter 51 – Male Glowworm Beetle

Subject:  What is it? Thought it was a wasp.
Geographic location of the bug:  Upstate SC USA
Date: 06/04/2020
Time: 11:31 PM EDT
Your letter to the bugman:  This is June 4th. Was 90°partly cloudy and humid. This was at 10:30pm. Cat caught and killed it. It is the size of an average wasp.
How you want your letter signed:  However

This is an adult male Glowworm Beetle.  Unlike Fireflies that have bioluminescent abilities, only the larval Glowworm glows.  The larval Glowworm is sometimes called a Railroad Worm.

Letter 52 – Male Glowworm Beetle

Subject:  Identification of insect
Geographic location of the bug:  Grand Rapids, MI
Date: 07/07/2020
Time: 06:35 PM EDT
Your letter to the bugman:  I don’t know what this insect is.  I found it on a door frame in the morning on a summer day.
Thank you for any information you can provide.
How you want your letter signed:  M.J. Moriarty

Dear MJ,
This is a male Glowworm Beetle.  According to BugGuide:  “mostly nocturnal; males come to lights.”

Letter 53 – Male Western Banded Glowworm Beetle

Subject: What the heck?
Location: Nevada County, CA.
June 19, 2016 11:31 am
Found in Nevada County CA. Can you tell me what this freakish thing is?
Signature: Carol Macarty

Dear Carol,
This is an adult male Glowworm Beetle probably the Western Banded Glowworm, Zarhipis integripennis, which is pictured on BugGuide.  While male Fireflies that flash with bioluminescence as adults signalling to females that respond by flashing back, male Glowworms do not light up and only  larviform female Glowworms glow in the dark to attract a mate.  

Letter 54 – Pink Glowworm

Subject: pink glow worm?
Location: northern california
May 16, 2015 10:11 pm
Please see my pic for both a photo and a description of the find. This happened May 14th in a rural area outside of Santa Rosa, CA. Oak woodlands. Is it a pink glow worm, adult female? Thanks!
Signature: Tony

Dear Tony,
Thanks so much for sending us your account of a female Pink Glowworm, Microphotus angustus, sighting.

Letter 55 – Pink Glowworm

Subject:  Pink Glowworm Sighting
Geographic location of the bug:  Julian, CA 93036
Date: 06/11/2019
Time: 12:58 AM EDT
Your letter to the bugman:  First time seeing this bug. June 11, 2019 at 4,200 altitude
How you want your letter signed:  Dianna Hess

Dear Dianna,
Thanks so much for sending in your awesome images of a Pink Glowworm, Microphotus angustus, both illuminated and illuminating.  The Pink Glowworm is actually a Firefly.

Letter 56 – Railroad Worm

Subject:  My kids must know what this is!!
Geographic location of the bug:  Coker, Alabama
Date: 08/06/2018
Time: 02:28 PM EDT
Your letter to the bugman:  My children have become bug lovers, like their mom!  They like to explore and are constantly trying to find “critters.”  Yesterday while we were playing in the creek near our home we found a HUGE millipede, a salamander, a crayfish, a lamprey, and this little guy/girl.  I’m pretty quick with google and I know basic names for most of what we find but this one stumped me!  Help us!!
How you want your letter signed:  Keep on finding bugs!!

We strongly suspect you did not find this Railroad Worm in the creek unless it fell in.  Railroad Worms or Glowworms are the bioluminescent larvae of Beetles in the family Phengodidae, and if it is still in your possession, you should look at it in the dark to witness the glow.  If you do that, please send in a photo of this Glowworm glowing.

Letter 57 – Railroad Worm

Subject:  Insect ID Please
Geographic location of the bug:  Shepherdsville, Kentucky
Date: 09/11/2021
Time: 07:37 PM EDT
Your letter to the bugman:  This insect was seen on 9/11/21 in Shepherdsville, Kentucky. Can you tell me what it is, please? Thank you!
How you want your letter signed:  Bugman

We never tire of posting good images of Railroad Worms or Glowworms.  Glowworms are bioluminescent.

Letter 58 – Railroad Worm

Subject:  Large Coleoptera larcae
Geographic location of the bug:  Monteagle TN
Date: 10/24/2021
Time: 11:07 PM EDT
Your letter to the bugman:  Found a large beetle larva while walking the dog tonight.
I would like to submit picture for iNaturalist but am stumped on ID. I have seen this species before.
How you want your letter signed:  Chris Waldrup

Dear Chris,
This is the larva of a Glowworm Beetle, commonly called a Railroad Worm because of its ability to glow green in the dark as an example of bioluminescence.  We believe your individual is in the genus Phengodes based on BugGuide images.  Here is a BugGuide image of a Glowing Glowworm.

Letter 59 – Railroad Worm, AKA Glowworm

Subject: caterpillar ?
Location: Northeast Georgia
September 17, 2012 8:11 am
Found this in my cat’s water bowl last night (September 16, 2012). Thought it was beautiful and just trying to identify it.
Signature: J. Childs

Dear J. Childs,
Your letter did not indicate if the creature was still alive or if it had drowned.  If the former, and if it is still in your possession, you might want to treat yourself to a little light show.  This is a Railroad Worm or Glowworm.  It will glow in the dark, producing a greenish bioluminescence that is quite impressive.

It was still alive and I wanted it to stay that way, so I let it go last night!  RATS!  Wish I could find it again to see it glow!  What type plants might I find this on?  I have some mints of different kinds near the area where it was found.  Would that be a possibility?
J

Glowworms are predators so you will not necessarily find them on specific plants.  The example from our archive was feeding on a millipede.  This University of Florida IFAS webpage also indicates they feed on Millipedes and it has much information on Glowworm biology.

Letter 60 – Railroad Worm, AKA Glowworm

Subject: Centipede Looking Creature
Location: Raleigh NC
September 27, 2014 11:02 am
I was out in my back yard walking around and I saw this bug crawling along on the ground. I pulled out my phone and took some pictures. Could you tell me what I saw?
Signature: Joe S.

Dear Joe,
If you had the ability to darken the surroundings, you would have had a nice surprise because this is a Glowworm or Railroad Worm.  They are bioluminescent, hence they glow at night.  Your individual is in the genus Phenogodes, and you can get additional information on BugGuide.

Letter 61 – Railroad Worm: Glowworm Larva

Subject: Snake like insect?
Location: Kershaw, South Carolina
August 8, 2015 10:35 am
Hi. So my mom and I recently discovered this insect in our house. He or She had the body of a centipede but only six legs. It seemed to be predominantly yellow with black bands of with red dots on them. We have never seen a bug like this and I’ve tried to find the name of it. When we found it, it was curling up so I didn’t get a high quality picture of it. It looks to me like a wireworm but none of the colors match up. Could you tell us what bug is this? Thank you
Signature: I’m not sure.

What a marvelous image of a Railroad Worm, an interesting common name for this Glowworm Larva.  Viewing the Railroad Worm in the dark will provide you with a wonderful light show.

Letter 62 – Western Banded Glowworm

Subject: Some kind of grub
Location: San Jose, CA
February 10, 2015 12:15 am
I found this guy in early Feb in a hurry to go under my chest freezer. It was pretty long, maybe 3″ or so, and was moving pretty quickly. Any ideas? Thank you!
Signature: Jonathan

Dear Jonathan,
Had you turned out the lights, you might have been treated to a light show from this Western Banded Glowworm, Zarhipis integripennis.