Flannel Moth: All You Need to Know for Your Next Encounter

The Flannel Moth is a fascinating insect that many people may not know much about. This creature is not only intriguing in appearance but also has some unique characteristics that set it apart from other moths. In this article, we will explore everything you need to know about Flannel Moths by focusing on their appearance, behavior, and where they thrive.

Flannel Moths are known for their peculiar appearance, with adults having vibrant colors and thick hair covering their bodies. One example is the White Flannel Moth (Norape ovina), which has an all-white appearance and extensive hair around the head and thorax. In contrast, the Southern Flannel Moth has a more colorful appearance, with orange to yellow fur and a wingspan of 1-1.5 inches source.

Behavior-wise, Flannel Moths are nocturnal, and their caterpillars are known as Puss Caterpillars. These caterpillars have a unique appearance, such as the yellow and black polka-dot pattern on the White Flannel Moth caterpillar source. They are commonly found in a variety of habitats, including gardens, woods, and fields. However, it’s essential to be cautious around Puss Caterpillars, as they can cause painful stings when touched.

Flannel Moth Overview

Megalopygidae Family

  • Family of moths
  • Known for stinging caterpillars
  • Painful stinging hairs

The Megalopygidae family consists of flannel moth species known for their stinging caterpillars. These moths have caterpillars with painful stinging hairs that can cause discomfort upon contact.

Megalopyge Opercularis

  • Known as the puss moth caterpillar
  • Found in Texas
  • Infest shade trees and shrubs

The Megalopyge opercularis, also known as the puss moth caterpillar or “asp”, is commonly found in Texas1. These caterpillars often infest shade trees and shrubs around homes, schools, and parks1.

Southern Flannel Moth

  • Cocoons remain on plants
  • Adult moths: 1-1.5 inch wingspan
  • Females larger than males
  • Yellowish front wings, creamy yellow hind wings

The Southern flannel moth (Megalopyge opercularis) has distinct cocoons that can be found on plants even after the adults have emerged2. Adult moths have a wingspan of around 1-1.5 inches, with females being larger than males2. Their front wings are yellow while their hind wings are creamy yellow2.

Feature Megalopyge Opercularis Southern Flannel Moth
Commonly known as Puss moth caterpillar Asp
Location Texas Southern US
Infests Shade trees, shrubs Host plants
Adult wingspan 1-1.5 inches 1-1.5 inches
Females Larger than males Larger than males
Front wings Yellow Yellow
Hind wings Creamy yellow Creamy yellow
Painful stinging hairs (caterpillar) Yes Yes

Life Cycle and Physical Features

Caterpillar Stage

  • The caterpillar stage of flannel moths is known for their venomous spines.
  • They feed on different plants, such as oak and other plants found in Texas.

The flannel moth larvae, or caterpillars, have prolegs that resemble snakes. These venomous spines can cause a painful sting similar to a snake bite, if touched. Caterpillars are subject to changes in appearance as they grow, and the stage before pupation is called the pre-pupal stage.

Puss Caterpillar

The puss caterpillar is one of the most recognizable stages of a flannel moth’s life cycle. Its unique features include:

  • Dense and long, velvet-like hair
  • Resembles a soft, cottony tuft
  • Hides the venomous spines beneath its hair

This particular caterpillar stage can be found on oak trees in Texas and is avoided by many due to its painful sting.

Adult Moth Stage

At the adult moth stage, flannel moths display a distinct appearance and a few noteworthy characteristics:

  • Chunky-bodied with a fluffy appearance
  • Wingspan ranging from 1 to 1.5 inches
  • Females are usually slightly larger than males
  • Colors vary: whitish, yellowish, or brownish with few markings
  • Males have featherlike antennae, while females have thin antennae

Here is a comparison table of the three stages discussed above:

Stage Appearance Size Harmful?
Caterpillar Venomous spines Varies Yes
Puss Caterpillar Velvety hair Varies Yes
Adult Moth Fluffy, chunky body 1-1.5 inches No

At the end of the caterpillar stage, flannel moths experience a pupal phase, during which they create cocoons. These cocoons are tough and may remain on plants even after adult moths emerge. The life cycle then continues as adult moths mate, lay eggs, and start the process over again.

Habitats and Distribution

Trees and Shrubs

Flannel moths, also known as puss caterpillars, are commonly found on a variety of trees and shrubs. For example, they typically inhabit:

  • Oak trees
  • Elm trees
  • Citrus trees

These moths may also be found on other plant species that grow in their geographical range.

Geographical Range

The distribution of flannel moths varies across North America. They can be found in regions such as:

  • Florida
  • Southern Canada

Their presence in these areas depends on the availability of suitable habitats and host plants for their caterpillar stage. In general, flannel moths are more common in warmer regions compared to colder areas.


  • Wide distribution across North America
  • Adaptability to a variety of trees and shrubs


  • Limited to areas with suitable habitats and host plants.

Stinging and Medical Implications

Symptoms and Severity

The sting from a flannel moth caterpillar, also known as a puss caterpillar, can cause various symptoms depending on the individual and the species. Some common symptoms include:

  • Pain, often described as burning or stinging
  • Swelling and redness at the sting site
  • Nausea or abdominal pain in severe cases
  • A raised, erythematous rash called erucism, as observed in the white flannel moth caterpillar

In rare cases, individuals may experience difficulty breathing or severe allergic reactions.

Treatment and First Aid

If stung by a flannel moth caterpillar, take the following steps:

  1. Remove any remaining spines using tweezers or a piece of tape.
  2. Clean the area with soap and water.
  3. Apply a cold pack to reduce swelling.
  4. Take an antihistamine or use a topical steroid cream to alleviate itching and rash.
  5. Seek medical attention if symptoms worsen or do not improve within a few days.


To minimize the chance of getting stung by a flannel moth caterpillar, follow these tips:

  • Be vigilant when outdoors in environments where they may be present.
  • Wear protective clothing such as long sleeves, pants, and gloves when in risky areas.
  • Do not touch or handle unfamiliar caterpillars.

Comparison table: Flannel Moth Caterpillar vs. Harmless Caterpillars

Feature Flannel Moth Caterpillar Harmless Caterpillar
Venomous spines Yes No
Painful sting Yes No
Medical attention needed Sometimes No

In summary, stings from flannel moth caterpillars can cause pain, swelling, rashes, and even severe allergic reactions. Treatment involves removing spines, cleaning the area, and using cold packs, antihistamines, or topical steroid creams. To prevent stings, exercise caution when outdoors, wear protective clothing, and avoid touching unfamiliar caterpillars.

Control Measures and Management

Pesticides and Biological Control

Pesticides can be used to treat infested articles to repel fabric pests like flannel moths. The vapors from these active ingredients are lethal to all stages of fabric pests and are especially effective when used to kill older stage clothes moth larvae or carpet beetles. However, use caution with pesticides, especially around children and those with breathing problems. Alternatively, biological control methods using natural predators can be employed to manage flannel moth populations.

Moth Removal

To prevent flannel moth infestations in your home, consider using cedar chests or airtight containers for storing clothes and textiles. Maintain low humidity levels inside buildings to create an unfavorable environment for moth development. Regularly inspect and clean clothing, rugs, and upholstered furniture to minimize the chances of moth colonization.

Natural Predators

Southern flannel moths (lepidoptera) are found mostly in deciduous trees in the Dallas area. They are cream-colored, delicate insects covered with yellow to orange hair. These moths have defensive setae that can cause irritation to humans. Natural predators, such as birds and parasitic wasps, can help control the moth population and keep them in check. Encouraging these predators to inhabit your garden can be an effective measure to prevent moth infestations.

Appearance and Recognition

Colors and Patterns

Flannel moths are known for their fluffy appearance with hairy bodies, legs, and wings. These moths can be found in shades of whitish, yellowish, or brownish colors. Their strikingly colored hairs serve as a defense mechanism. Here are a few examples of flannel moth colorations:

  • Cream-colored
  • Orange

Mouthparts and Legs

Flannel moths have prominent mouthparts and hairy legs. These features can help identify them from other moth species. Now, let’s look at some specific characteristics:

  • Strong mouthparts
  • Hairy legs
  • Blunt wings

A table comparing flannel moths with other moths:

Feature Flannel Moth Other Moths
Color Whitish, yellowish, or brownish Varies widely
Hairs Strikingly colored hairs for defense May or may not have hairs
Mouthparts Prominent, strong mouthparts Varies
Legs Hairy legs May or may not have hairy legs
Wings Blunt wings, with wavy hair Varies

The unique appearance of flannel moths, also known as “asps,” is crucial in their identification and makes them stand out from other moth species.


  1. https://citybugs.tamu.edu/factsheets/biting-stinging/others/ent-3010/ 2

  2. https://extensionentomology.tamu.edu/insect/southern-flannel-moth/ 2 3

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 – DANGER: Mexican Flannel Moth Caterpillar


WTB Saves Our Vacation!

Stinging Flannel Moth Caterpillar

WTB Saves Our Vacation!
September 23, 2010
Hello Daniel,
(I’ve tried to send this note before, so ignore it if you’ve received an earlier version.)
In February of this year, my wife and I visited Isla Mujeres, an island just off Cancun.  I was thrilled when my wife discovered a caterpillar on the Sea Grape hedge near our hotel.  But something about it seemed familiar, and threatening.
Sure enough, I was recalling a WTB post a year earlier, February 2009, filled with frightening infomation about this exact species of Flannel Moth caterpillar, on the very same island!
As your fans start dreaming of a vacation in the tropics, I’d like to caution them to be wary of critters they don’t know.  My wife wanted to touch this caterpillar, and that could have been real trouble.  (I did let her lightly brush her fingers over the ends of the long hairs, but not the nasty shorter bristles.)
Sea Grape is a beautiful and very common shrub/tree there, and is frequently used in landscaping.  The local hotel staff doesn’t warn guests, and the caterpillars are attractive, at least to bug-nuts like me and my wife.
The caterpillars were in the later stages of development when we were there in mid-February, and some were spinning their cocoons.  It may be that there are several generations in the course of a year, so be on guard whenever you’re there.  They are wonderful subjects for photos, and they’re not going to attack you.  It’s look-but-don’t-touch.
Thank you WTB for your excellent work, and for saving our vacation!
Don J. Dinndorf
St. Augusta, MN

Stinging Flannel Moth Caterpillar

Dear Don,
We did not receive your previous emails, or we overlooked them, so we are very happy you resent.  We are also pleased to hear our humble service was able to contribute to your pleasant vacation.  The stinging Mexican Flannel Moth Caterpillar in the genus
Megalopyge, which has been documented on our website in the past, might be one of the worst stinging caterpillars in the world.  Your excellent photos are greatly appreciated and we hope we are able to help other tourists to Mexico and Central America with this information.

Stinging Flannel Moth Caterpillar spins cocoon

Letter 2 – Unknown Mexican Moth is Acraga coa


Orange Furry Moth
Mon, Oct 27, 2008 at 7:35 PM
I saw this moth on my kitchen window at night in Jocotepec, JAL, Mexico. He was about one inch long. The first photo is him on a piece of white paper and the second photo is him on a piece of glass, shot from the other side.
David Brownell
Jocotepec, JAL, Mexico

Unknown Mexican Moth
Unknown Mexican Moth

Hi David,
Your photos are spectacular. We don’t know what this moth is and we don’t have time to research at the moment as we must dash off to work, but we are posting and hope someone can provide an answer. Here is what Julian Donahue, our neighbor the lepidopterist had to say: “It’s in the family Dalceridae. The expert on the group is Dr. Scott Miller at the Smithsonian Institution. You might want to send him the photo to get a species name. Julian”
With that information, we located a mounted specimen of Acraga coa that looks promising, but the mounted specimen lacks all the charm of David’s photographs.

Unknown Mexican Moth
Unknown Mexican Moth

Spectacular picture!  It is a Dalceridae, and the species is Acraga coa.
Dr. Scott Miller
The Smithsonian Institution

Letter 3 – Unknown Costa Rican Moth is Acraga coa


orange moth in costa rica
Fri, May 15, 2009 at 5:07 PM
I found this moth in costa rica on the eastern coast near panama, what kind is it?
gandoca, costa rica

Unknown Moth
Acraga coa

Dear Jes,
We are relatively certain we posted this species or a very similar species in the past, but alas, we have not been able to locate an image in our vast archives. We suspect this may be an individual in the family Lasiocampidae that includes the Tent Caterpillar MOths and Lappet Moths. Hopefully, one of our readers will write in with a correct identification.

Unknown Moth

Update: Sun, May 17, 2009 at 9:04 AM
Hi Bugman:
It’s a beautiful shot, but a little hard to identify because of the head-on view. I believe it is in the family Dalceridae (Dalcerid moths), a relatively small family of neotropical moths. Orange coloration and very fuzzy legs are typical for the group. The Dalcerids are related to the Megalopygidae and Limacodidae, and the three families are sometimes collectively known as “slug caterpillars”. Whereas many of the Megalopygidae and Limacodidae possess stinging hairs, Dalcerid larvae are covered in gelatinous tubercles which probably deter attacks from predators. I think Jes’s moth may be in the genus Acraga , possibly A. coa . Regards.

Hi Daniel:
I just found the previous post of this moth on WTB (I should have checked first). Excellent photos and an identification by Dr. Scott Miller at the Smithsonian Institution.

Thanks Karl,
It is a little sad that we could not quickly locate this identification in our own archives.

Update:  August 5, 2012
In trying to clean up some unidentified tags, we thought we would provide another link to this unusual moth on the Moths of the Andes page.

Letter 4 – Empty Southern Flannel Moth Cocoons on Oak Tree


Subject: Insect Case Identification
Location: Gulf Shores, Alabama
March 17, 2016 10:17 am
Attached is a picture of an insect case found on some small oak trees. We would like some identification of the insect that would deposit such a case.
Signature: Gulf State Park Nature Center


We have to call these Cocoons because they look like larvae made them before pupating and eventually emerging.  We will research in the morning.

I have been searching too.  Could it be a Megalopyge opercularis (southern flannel moth cocoon)?
Kelly Reetz
Naturalist – Gulf State Park

Hi Kelly,
We received a comment indicating the cocoons belong to the Southern Flannel Moth.  This BugGuide image supports that ID.  They appear to be empty, indicating the adult Southern Flannel Moths have already emerged.

Letter 5 – Black Waved Flannel Moth


Subject: Black waved flannel moth
Location: Fredericksburg, Virginia
June 30, 2017 12:46 am
I’m pretty certain that these photos are of the Black Waved Flannel Moth (checking against bug guide)(and reading that you have had endless photos of them). …I got no absolute confirmation from Bugguide but there were many photos of identical moths. The information I can’t seem to find, is what relationship these moths have to the Puss Caterpillar. They seem to be separate ….there are the megalopygea opercularis and then there are the species Lagoa crispata. Both Flannel Moths? Similar looking caterpillars?.
And the Puss Caterpillar is VENOMOUS but I can’t find information on how venomous the Lagoa crispata is. Or the specific caterpillar. The internet is conflicting. Are they venomous and are they AS venomous?
Signature: Susan Warner

Black Waved Flannel Moth

Dear Susan,
All the images you provided are details.  We wish you had provided a standard dorsal view of the entire moth.  We believe your identification of the Black Waved Flannel Moth is correct, and the antennae indicate this is a male moth.  BugGuide does indicate:  “Caution, Hairs on caterpillar highly irritating, as in all of this family!”  So, the family Megalopygea includes both
Lagoa crispata and Megalopyge opercularis, but they are classified in different genera within the family.  According to an article on the Asp, Megalopyge opercularis, by David M. Eagleman on EaglemanLab:  “Envenomation from the spines of the caterpillar causes severe pain, burning, swelling, nausea, abdominal distress, and headache. … The best known venomous caterpillar in the American south- west is the puss moth caterpillar, Megalopyge opercularis, commonly called an asp, wooly asp, Italian asp, opossum bug, wooly slug, and el perrito. It is considered one of the most toxic caterpillars in North America.”  We agree with you that the two caterpillars look very similar, and it is entirely possible that some Asp postings on our site are misidentified, and are actually the caterpillars of the Black Waved Flannel Moth.  Regarding the relative venomousness of the two species, we cannot provide you with a scale or data, but we do know that irritation and reactions to stings and bites from insects vary from person to person.  Some folks are highly allergic to the sting of a Honey Bee while other folks are barely affected at all beyond the initial pain of the sting.  Some folks have tremendous reactions to the bite of a Lacewing, while others are not affected at all.  We would urge you to refrain from handling both species, though again, distinguishing between the two might be difficult.  It is also possible that the sting of the Black Waved Flannel Moth caterpillar has not been studied as extensively as has the Asp.  Of the entire Flannel Moth family Megalopygidae, the Auburn Agriculture page on Stinging Caterpillars states:  “Flannel moth caterpillars, like slug caterpillars, do not exactly fit the description of the typical lepidopterous larva. Structurally they differ in having seven pairs of prolegs rather than five (or less) pairs common to typical caterpillars. Most are clothed with fine, long, silky hairs. There are no conspicuous large, threatening, bristle-bearing “horns” to warn of danger; however, concealed within the hairy coats are venomous setae capable of producing severe reactions.”  While the Black Waved Flannel Moth is not discussed in the article, Auburn Agriculture does clearly state:  ”  Puss Caterpillar (Megalopyge opercularis) The puss caterpillar (the adult is called southern flannel moth) is our most ‘dangerous’ stinging caterpillar. Contact may produce severe reactions including: intense burning and nettling of the skin; severe pain; reddening and inflammation; development of pustules and other lesions; numbness; swelling, which may sometimes be extensive; and nausea. Pain may persist from one to twelve or more hours. In some instances, victims have required medical attention. The larva is urticating in all stages, but severity of the reaction is generally proportional to size. Also, newly molted skins retain stinging capabilities.”  There you have it.  According to Auburn Agriculture, the Asp is “our [North American] most ‘dangerous’ stinging caterpillar.”

Subject: supplement photo (dorsal)
Location: Frederericksburg
June 30, 2017 8:19 pm
I have a dorsal view of the moth…better overall….not just the detail….of the Black Waved Flannel Moth photo i sent, to help make an ABSOLUTE identification.
It seems that both the puss variety and this one are all something to avoid. I wanted to know if seeing this moth might indicate puss or super venomous caterpillars in the vicinity. A friend in the southwest once had to go to the ER after leaning on a puss caterpillar.
Subject: Black waved flannel moth
Location: Fredericksburg, Virginia
June 30, 2017 12:46 am
Signature: Susan Warner

Black Waved Flannel Moth

Dear Susan,
Thank you for sending in a supplementary dorsal view of a Black Waved Flannel Moth.

Letter 6 – Black Waved Flannel Moth Caterpillar


Subject: WTB
Location: East of Shamrock Texas
August 24, 2017 10:31 am
found on one rose bush. I have 11 rose bushes. I only spotted one of these hairy cocker spaniel looking catepillars. I wont touch it.
Signature: cowchipper

Black Waved Flannel Moth Caterpillar

Dear cowchipper,
This is a Flannel Moth Caterpillar from the family Megalopygidae, a group that contains the infamous Asp.  You were wise not to touch as many Flannel Moth Caterpillars are capable of stinging.  We believe we have identified your individual as a Black Waved Flannel Moth Caterpillar,
Lagoa crispata, thanks to this BugGuide image.  According to BugGuide:  “Caution, Hairs on caterpillar highly irritating, as in all of this family!”

Black Waved Flannel Moth Caterpillar

Letter 7 – Bug of the Month October 2015: Southern Flannel Moth


Subject: What kind of bug is this?
Location: Alabama
September 30, 2015 2:07 pm
Please tell me what kind of bug this is.
Signature: Thank you. Tammy p

Southern Flannel Moth
Southern Flannel Moth

Dear Tammy p,
This is a Southern Flannel Moth,
Megalopyge opercularis, and your individual is a male as evidenced by the feathery antennae and pronounced markings.  Though you might not be familiar with the adult moth, many folks in the South are quite familiar with its larval form, commonly called a Puss Caterpillar or Asp.  According to BugGuide:  “Caution, caterpillars have painful sting.  Occasionally, in outbreak years, puss caterpillars are sufficiently numerous to defoliate some trees (Bishopp 1923). However, their main importance is medical. In Texas, they have been so numerous in some years that schools in San Antonio in 1923 and Galveston in 1951 were closed temporarily because of stings to children (Diaz 2005).”  Images of the Asp are much more common on our site that those of the adult Southern Flannel Moth.  Since it is the first of October, we have selected your submission to be our featured Bug of the Month for October 2015.

Asps from our archive
Asps (image from our archive)

Letter 8 – Flannel Moth


Subject: Fuzzy Flying Yellow Insect
Location: Anderson, SC
July 14, 2013 10:42 pm
Hello Bugman,
My brother took this photo in Anderson, SC. I am very curious to know what kind of bug it is.
Signature: Thank you, Rachel

Flannel Moth
Flannel Moth

Hi Rachel,
This is one of the Flannel Moths in the genus
Megalopyge, most likely the Southern Flannel Moth, Megalopyge opercularis, which you may find on BugGuide.  The stinging caterpillar is sometimes called an Asp

Letter 9 – Flannel Moth from Panama


Subject:  Is this a moth?
Geographic location of the bug:  https://goo.gl/maps/SqMDrFV5LQvREYKS6
Date: 05/07/2019
Time: 06:21 PM EDT
Your letter to the bugman:  My girlfriend found this weird looking bug in the park near our home, looks like a weird moth to me, any idea what it actually is?
How you want your letter signed:  Edmundo

Flannel Moth

Dear Edmundo,
Though we have not located an exact visual match, we are confident this is a Flannel Moth in the family Megalopygidae, and it looks very similar to a member of the family pictured on the UGA Costa Rica blog.

Update:  Insecta.pro. Thanks to a comment from Cesar Crash who identified this as a member of the genus Perola, we were able to find this link on

Letter 10 – Flannel Moth from Panama


Subject:  Unidentified Moths of Panama
Geographic location of the bug:  Boquete, Panama
Date: 10/01/2017
Time: 01:49 PM EDT
I find amazing, striking moths and other insects every morning on the outside walls of my house in Panama. I don’t have access to a field guide to help me identify these beauties.
How you want your letter signed:  Nora

Flannel Moth: Megalopyge albicollis we believe

Dear Nora,
This is a Flannel Moth in the family Megalopygidae, and we believe it is in the genus
Megalopyge.  This FlickR image of Melagopyge tharops looks very close, but we believe this FlickR image of Megalopyge albicollis is a much better match, however the same species on Moths of the Amazon and Andes looks different.  Flannel Moth Caterpillars should be handled with extreme caution as many species are capable of stinging.  Please, in the future, confine your submission to a single species unless there is another good reason to submit unrelated species in the same posting. 

Letter 11 – Spanish Moth from the Virgin Islands


Furry headed moth
March 4, 2010
This was on the wall at my boyfriend’s condo around 8PM. It’s head is furry- I would pet it if I knew it wasn’t poisonous, but I wouldn’t want to hurt the bug either. Anyhow, if you could identify it, that would be great. I’ve never seen one around here before, and there are actually two of them on the wall
Michelle Miller
St. Croix, USVI

Spanish Moth

Hi Michelle,
Your moth reminds us a bit of a photo we received two months ago that was identified as a Mangrove Flannel Moth.  Your moth is a different species, but we suspect it might be a Puss Moth or Flannel Moth in the same family, Megalopygidae.  Karl always does a great job with difficult identifications, and perhaps he will be able to come up with a match.

Spanish Moth

Hi Daniel and Michelle:
I like the frowning face on its back when the wings are closed, and the fuzzy headgear. This is actually an Owlet Moth ((Noctuidae: Hadeninae), specifically a Spanish Moth (Xanthopastis timais). The species is extremely widespread, ranging from New York to Argentina and including all of the Caribbean. The background color ranges from white to bright pink but the rest of the markings are fairly consistent and distinctive. It’s a very pretty moth – thanks.

Letter 12 – Flannel Moth from Mexico likely Thoscora acca


Subject: Fuzzy looking bug
Location: central-south Mexico – Tabasco/Campeche
February 4, 2013 2:49 pm
Found this bug in December while road-triping through Mexico. Stopped at a gas station and there it was, lying on the side of the building.
Hope you can help.
Signature: Kelly

Flannel Moth

Hi Kelly,
Based on similar looking moths on BugGuide, we believe this is a Flannel Moth in the family Megalopygidae, but we have not had any luck matching an exact photo.  Perhaps it is in the genus
Megalopyge , and it looks somewhat similar to this image of Megalopyge bissesa from The Moth Photographers Group, but again, it does not appear to be an exact match.  The Hétérocères de Guyane Française Megalopygidae page has numerous mounted specimens, but none that we can say conclusively looks like your individual.  Perhaps one of our readers will be able to provide assistance.

Karl agrees with Flannel Moth ID.
Hi Daniel. Based on overall appearance, posture and visible wing venation I would have to agree that it is probably a Flannel Moth (Megalopygidae). I think it is probably in the genus Thoscora, a neotropical genus with seven or eight species. Unfortunately, online information is extremely sparse for all the species and I can’t come up with a conclusive identification. It looks very close to Thoscora acca, but I couldn’t find any information that this species occurs north of Costa Rica. However, this may just be due to a lack of information. The Area de Conservación Guanacaste (ACG) site shows an assortment of mounted T. acca, and the Hétérocères de Guyane Française Megalopygidae page that you linked to has several subspecies of T. acca (other sites regard these as distinct species) as well as two other species. Mounted specimens offer some clear advantages for identification as all features are revealed.  However, I find that other information such as natural posture is lost, which sometimes makes it difficult to recognize a species when it is compared to a photo of a live specimen.  My best guess would be that it is Thoscora acca. Regards.  Karl

We like your identification Karl.  Has anyone told you that you are awesome lately?

Wow! Thanks so much for replying so quickly! I thought the little guy must have been some sort of moth, but wasn’t exactly sure.  The camera-phone pic doesn’t do it justice, and I was eager to find its identity so I could properly depict it in some of my artwork.
Thanks again!

Letter 13 – Flannel Moth from Peru


Subject:  Undetermined moth from Chanchamayo, Peru.
Geographic location of the bug:  Near Naranjal, Chanchamayo, Junin, Peru.
Date: 01/30/2019
Time: 10:23 PM EDT
Your letter to the bugman:  The body and wing shape are similar to a sphingid but the antennae are all wrong.
Locality was near Naranjal, Chanchamayo Province, Junin Region, Peru on January 10th, 2019 at about 1,020 m elevation. This was the morning the rainy season began for the locality. On the dorsal side of the abdomen there were broad, horizontal bands of black coloration, maybe four or five in number – a personal observation, not visible in the photo. It was of medium size for a moth yet small for a sphingid, probably with a wingspan close to or a little more than three inches.
The feathered antennae are what throw me as I am not familiar with any hawk moths with anything close to the resemblance. To me, it is visually similar to a Giant Leopard Moth (it isn’t one) but once again, the antennae are not like most tiger moths.
Any ideas or guesses, even just the family would be very welcome.
How you want your letter signed:  Kevin

Flannel Moth perhaps

Dear Kevin,
We agree this is not a Sphinx Moth.  We believe it is a Flannel Moth in the family Megalopygidae, or possibly a Carpenter Moth or Goat Moth in the family Cossidae.  We have contacted Lepidopterist Julian Donahue to get his input.  Meanwhile, we will begin searching images of Megalopygidae from South America.

Julian Donahue provides a family identification.
Not a cossid. It’s Megaloypygidae.

Julian Donahue provides additional information.
It’s Podalia orsilocha (or orsilochus, depending on the source), in the Megalopygidae.
Attached is an image of both sexes from plate 162 of Vol. 6 of Seitz, Macrolepidoptera of the World.
Complete life history, with photos (presumably by Dan Janzen and Winnie Hallwachs) from the Guanacaste Province of Costa Rica is here:

Google the species and you’ll find numerous additional websites.

Podalia orsilocha

Yes, that is it!
As soon as I Googled the Latin name, there was a nice video link for YouTube with footage of the moth – exactly like the specimen I found.
You all are very good – please pass along my thanks to Julian Donahue as well.
Many thanks!

Letter 14 – probably Flannel Moth from French Guiana


Caterpillar from French Guiana
Good morning,
I am curious about the possible ID of this beautiful hair-piece. It was photographed in French Guiana in the 1980s. Sorry, the scan of the slide is less than perfect.
Christian Feuillet

Hi Christian,
Sadly, despite Maria Sybilla Merian’s groundbreaking work on caterpillar metamorphosis of Amazon Lepidoptera at the end of the 16th Century, much of the insect life in the rain forest remains unknown, little studied, and assuredly never seen by non-natives. We believe this is some species of Flannel Moth Caterpillar in the family Megalopygidae. Flannel Moth Caterpillars, known as Puss Moths or Asps in parts of the southern USA, have stinging hairs that discharge venom. The sting of a Puss Moth caterpillar is considered by the Ohio State University FactSheet website on Stinging Caterpillars to be: “the most severe of all the stinging caterpillars.”

Letter 15 – Southern Flannel Moth


Subject: Never seen this till NOW
Location: Conroe, Texas
May 9, 2014 11:10 pm
I woke up on morning at about 9-10AM the day looked foggy as if it had showered the night before. I let my dogs out my backdoor and I see this orange insect attached to the outer side of the glass of door. I looked closer at it and it looked furry/fuzzy had two white antennae flipped back towards it sides almost. I noticed it had 3 black legs on one side from the point of view I held. Which would mean it had 6 black legs in total. I looked towards its bottom and it looked like it had wings but not the butterfly kind but the beetle kind (short and tucked in) No Idea what it is but it has been bothering me. I posted it in social media and have yet to find an answer as to what the insect is.
Signature: Brandi Hernandez

Southern Flannel Moth
Southern Flannel Moth

Hi Brandi,
When social media fails you, turn to What’s That Bug?  This is a Southern Flannel Moth,
Megalopyge opercularis, and we verified our identification on BugGuide.  The stinging caterpillars of the Southern Flannel Moth which are called Asps, are more commonly encountered than the adult moths.

Wow! Y’all are quick! Thank You! Finally I can rest. Who knew touching them when they’re just caterpillars can be venomous though they look harmless because of their fuzzy appearance.
Thank You!

Letter 16 – Unknown Panamanian Caterpillar on Cashew Tree is Megalopyge lanata


Panama caterpillar
This beautiful creature was photographed at Coiba National Preserve in Panama, December 11, 2007, feasting on the leaves of a cashew tree. I’ve been searching the web for two days and have had no luck identifying it, except that it’s probably of the Arctiidae family. Can you help?
Amy Lowell
White Lake, MI

Hi Amy,
We cannot currently help you with an identification, but we will post your image in the hopes that our readership can assist. Identification of many tropical species can prove very frustrating.

Update: (04/07/2008)
Thanks Dan. The caterpillar is Megalopyge lanata. The following information is courtesy of Annette Aiello: “The caterpillar is a clear case of Megalopyge lanata (Megalopygidae). Perhaps the unnatural perspective (the photo appears to have been taken in portrait view and later rotated to horizontal) made it look to you as if there were more than the usual red verrucae. As well, I suspect that the caterpillar had molted very recently and perhaps had not yet eaten very much, so still was somewhat condensed.” If you’ve posted the photo already, you can add its identification. I appreciate your help very much
Amy Lowell

Thanks for the update Amy. We found images of the adult Megalopyge lanata after you provided us with a name. We also located a caterpillar image on a Smithsonian Tropical Research Institute Photo of the Week website. The caterpillar has stinging hairs.

Letter 17 – We Stand Corrected. Sadly, we cannot contact Velma and confess.


Asps and Wasps, easily confused
I haven’t had my question answered but have seen questions from Sept answered. Do I need a pic? If so, I don’t have one. My question again is below.
We have some bugs in our garage that I would like to know more about. We call them “asps” although I’m not sure this is the accurate name. Our garage is detached from our home not heated/cooled and dark most of the time. We noticed that sometimes they attach themselves to the siding on our house in something sort of like a cocoon. They are small, about 3/4 of an inch, look to be kinda “furry”, gray to brown in color. If you get stung by one it hurts like hell. I was stung on the inside of my forearm and felt pain all the way to my armpit. A call to poison control said the sting affects your lymph nodes and that was the pain I was feeling in my armpit area. The burning is awful and it took me a good 4-6 weeks to get rid of the itch. We think our dog may have been stung by one on the nose and boy did she suffer. Her snout was so swollen her eyes were almost shut and she had a nasty area on her nose at the point of contact.
We’d also like to know if there is anything we can do to get rid of them.
V. Hernandez
San Antonio, TX

Dear Velma,
I doubt that you were stung by an asp, which is in actuality the deadly snake that Cleopatra used to commit suicide rather than to submit to Caesar. Wasps, however, are a different story and actually fit your description. Some species of solitary wasps make a mud nest in protected areas like under the eaves or inside of a garage. They sting, and sensitive people could posibly be affected as long as you state. We are not doctors, so we can’t tell you much about your lymph nodes, and we have no extermination advice, that being a job for your local experts. Sorry for the delay in answering your letter. We truly have been swamped with letters. Thank you for your patience.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

11 thoughts on “Flannel Moth: All You Need to Know for Your Next Encounter”

  1. (I had to look dorsal up in the dictionary)….I have a dorsal photo….I will post it in the normal way because I’m not sure how to post it in a comment….


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