Imperial Moth: All You Need to Know in a Quick Guide

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The Imperial Moth, scientifically known as Eacles imperialis, is a fascinating and beautiful creature found in North America. This large, eye-catching species is mostly active during nighttime, and its brilliant colors can range from bright yellow to various shades of brown, burgundy, or green.

Adult moths have a substantial wingspan that can reach four to five inches, with females being slightly larger than males. Their wings display a unique pattern of yellow and red-brown spots, making them difficult to confuse with any other species. During the caterpillar stage, the Imperial Moth can grow up to 5.5 inches in length and display different shades of green or brown depending on their form.

Imperial Moths lay their eggs on host plant foliage, and the caterpillars feed on the leaves until they’re ready to pupate. They spend the winter in the soil and emerge as adults during June or July. While their life cycle may be intriguing, it’s their striking appearance that continues to draw attention from both scientists and enthusiasts alike.

Imperial Moth Basics

Eacles Imperialis

The Imperial Moth, scientifically known as Eacles imperialis, is a species of moth that belongs to the family Saturniidae and the order Lepidoptera. This majestic creature is known for its large size and vibrant colors.

Physical Appearance

Imperial Moths are quite striking in their appearance. They have a few distinct features:

  • Yellow base color with spots and speckles of pink, orange, or rusty pale purple
  • Wingspan of 4 to 5 inches
  • Males have more feathery antennae

Imperial Moth caterpillars also exhibit a range of colors and can grow up to 5.5 inches in length. They are usually found in two forms:

  • Green form (light to dark green)
  • Brown form (orange to dark brown to nearly black)

Range and Distribution

The Imperial Moth has a significant range and distribution across North America:

  • Found from southern New England to the Florida Keys
  • Extends west through the southern Great Lakes region to eastern Nebraska and central Texas

Historically, the distribution of Imperial Moths went farther north, but they have been retreating from these areas since the mid-twentieth century.

Lifecycle and Development

Eggs and Larvae

Imperial moth females lay eggs on the foliage of host plants1. These eggs develop into larvae. Newly hatched larvae are small with few markings.

Caterpillar Development

Imperial moth caterpillars go through several instars2. As they molt, their appearance changes. By their final instar, they can grow up to 5.5 inches long3. Some key features include:

  • Variable appearance
  • Large size
  • Multiple instars

Pupa and Adult Stage

Imperial moth caterpillars transform into a pupa, which remains in the soil over winter4. In June or July, adult moths emerge. Adults are quite impressive, with a wingspan of four to five inches5.

Comparison of Female and Male Imperial Moth:

Characteristics Female Male
Size Slightly larger Smaller
Wings Bright yellow wings Less bright coloring
Wing markings Red-brown spots Fewer red-brown spots
Antennae Less feathery antennae More feathery antennae

Adult moths have a short life cycle, focused on reproduction6. Some highlights of pupa and adult stages:

  • Overwinter in the soil as pupa
  • Adult emergence in June or July
  • Display sexual dimorphism

Habitat and Host Plants

Host Plants for Caterpillars

Imperial moth caterpillars feed on a variety of host plants, some of which include:

  • Maple (Acer spp.)
  • Oak (Quercus spp.)
  • Pine (Pinus spp.)
  • Sassafras (Sassafras albidum)
  • Sweetgum (Liquidambar styraciflua)

These caterpillars have also been reported on other trees, like elm, basswood, cedar, and Norway spruce1.

Living Conditions for Adults

Adult imperial moths usually fly at night2. Their living conditions include forested areas dominated by their host plants. A comparison of the host plants preferred by the imperial moth caterpillars:

Plant Plant Family Preferred by Caterpillars
Maple Acer Yes
Oak Quercus Yes
Pine Pinus Yes
Sassafras Sassafras Yes
Sweetgum Liquidambar Yes
Elm Ulmus Rarely
Basswood Tilia Rarely
Cedar Cedrus Rarely
Norway Spruce Picea abies Rarely

It’s important to note the difference in living conditions between the caterpillars and adult moths. While caterpillars require host plants to feed on, adult moths primarily focus on reproduction and do not feed1.

Physiology and Adaptations

Wingspan and Patterns

  • The Imperial Moth has a large wingspan, reaching up to 5.5 inches.
  • Their wings display variable patterns, usually featuring yellow or orange backgrounds with dark black or burgundy markings.

Example wing colors:

  • Green
  • White
  • Orange
  • Purple
  • Dark

Spines and Spiracles

  • Imperial Moth caterpillars possess sharp spines for defense against predators.
  • Caterpillars also have spiracles, small openings for respiration along their bodies.

Camouflage and Variation

  • The Imperial Moth uses its variable wing patterns for camouflage to blend into its surroundings.
  • Different colors and markings provide a level of adaptability in varied environments.

Predator Defense:

  • Unique wing patterns
  • Camouflage capabilities
  • Caterpillar spines

Moth Variation:

  • Green
  • White
  • Orange
  • Purple
  • Dark
  • Black bands
  • Burgundy markings

Conservation and Threats

Population Decline

The imperial moth population has experienced a decline in North America. This decline is more significant in Canada and the Florida Keys. A contributing factor to this decline could be the loss of habitat due to urbanization.

Threats and Challenges

  • Parasitoids: Imperial moth caterpillars face threats from parasitoid wasps and flies.
  • Insecticides and Pesticides: The use of insecticides and pesticides may harm the imperial moth population. For example, the gypsy moth control program could indirectly affect imperial moths.
  • Habitat Loss: Urbanization leads to the loss of their habitat, which includes various host plants for caterpillars.
Threat Impact on Imperial Moth Example
Parasitoids Parasitic wasps and flies attack caterpillars Tachinid flies
Insecticides Exposure to insecticides may harm moths Gypsy moth control program
Habitat Loss Urbanization reduces suitable habitat Loss of host plants

Conservation efforts, such as reducing the use of insecticides and preserving native host plants, can help protect the imperial moth population. Education and awareness about these magnificent creatures and their importance in our ecosystem are essential for their survival.

Research and Classification

Scientific Studies

The Imperial Moth, belonging to the Lepidoptera order, has been studied for its distribution, decline, and nutritional ecology in the Journal of Research on the Lepidoptera. Researchers have particularly focused on relictual islandic populations.


Imperial Moth belongs to the subfamily Ceratocampinae and carries the scientific name Eacles imperialis imperialis.


Several subspecies of the Imperial Moth have been identified, including:

  • Eacles imperialis pini
  • Eacles imperialis decoris
  • Eacles imperialis opaca
  • Eacles imperialis quintanensis
  • Eacles imperialis cacicus
  • Eacles imperialis magnifica
  • Eacles imperialis tucumana

These subspecies can be compared based on their morphological differences and distribution. For example, E. i. pini is predominantly found in pine forests, while E. i. decoris has a distinct pattern on its wings.

Subspecies Main Feature Distribution
E. i. pini Pine forest inhabitant North America
E. i. decoris Distinct wing pattern South America
E. i. opaca Darker coloration South America
E. i. quintanensis Unique markings Central America
E. i. cacicus Bold wing coloration Central America
E. i. magnifica Large size South America
E. i. tucumana High-altitude distribution South America

Interesting Facts and Trivia

Imperial moths are fascinating creatures that are a part of the royal moth family. These nocturnal insects catch many people’s attention for their size and striking appearance. Let’s explore some interesting facts and trivia about the Imperial Moth.

The Eacles imperialis is known as the Imperial Moth. Native from Canada to Argentina, these moths are quite large, with some individuals boasting a wingspan of up to 5.5 inches. They are typically yellow with pink, orange, or rusty pale purple spots and speckles on their wings.

Their caterpillars are interesting on their own, displaying a variety of colors ranging from:

  • Light to dark green
  • Light to dark brown
  • Burgundy

Full-grown caterpillars can reach lengths of 3-5½ inches. They have 4 spiny horns located on the front of their body.

The Imperial Moth has a particular relationship with its environment. Female moths lay eggs on the foliage of host plants, where caterpillars feed on leaves from trees like:

  • Maple
  • Oaks
  • Pines

When it is time to pupate, they head down to the soil, digging a burrow where they’ll transform into adult moths. This pupation process takes place underground, helping them stay protected from predators and harsh weather conditions.

A comparison between Imperial Moths and other large moths, such as the Luna and Polyphemus moths, shows these three moths have distinct design features. For example, Luna moths have light green wings with long twisted tails, while Polyphemus moths have a similarly large wingspan, with light green wings and transparent spots.

With such unique features and an intriguing life cycle, Imperial Moths truly stand out among butterflies and moths, making them a captivating subject for nature lovers and entomologists alike.


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Reader Emails

Over the years, our website, 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 – Imperial Moth


large yellow and brown moth
July 9, 2010
saw this on the sidewalk in downtown omaha. it was still alive although not interested in flying. i moved it off the sidewalk and when touched it would flip over. it also appears to have a hole in its head one side…maybe a parasite?
omaha, ne

Imperial Moth

Dear Miles,
Your moth is a male Imperial Moth,
Eacles imperialis, and it is a male moth based on the amount of purple/brown on the wings.  The female is more yellow.  Imperial Moths do not feed as adults, and they only live a few days, perhaps a week at most.  Their sole purpose as adults is the perpetuation of the species, though they also provide food for many predators.  Perhaps this moth was attacked by a bird and then abandoned.

Letter 2 – Imperial Moth


Subject: Daniel…1 more for a cold beer! hehe
Location: N. Mississippi outside of Memphis, TN.
July 11, 2012 10:09 am
Hey again!
I looked on the site for this last ID. She/he was HUGE! Some kids were going to kill it on the gas pump. I threatened them within an inch of their life and gently allowed ”her” to crawl up on my hand. I got back to the car, and she rode on my thigh (had shorts on) all the way home. I then took her to a woody area behind the house and hid her in the bushes till she decided to fly away on her own. She was absolutely MAGNIFICIENT!
Thanks for the help!
Signature: Stephanie Berry

Imperial Moth

Hi again Stephanie,
This is the second photo we have posted in the past 24 hours of a lovely insect accessory.  The first was of a Sphinx Moth.  This is an Imperial Moth and we believe she is a female.  According to BugGuide:  “Adult: wings yellow, variably spotted and shaded with pinkish, orangish, or purplish-brown; male more heavily marked than female, especially in the south.”  Your individual is intermediate in coloration, so it could be a dark female or a light male.  Too bad the antennae are not visible as that helps to determine sex.  We also want to commend you on the dramatic rescue of this harmless Imperial Moth from a gang of ruffians at the gas station.  For that you are getting tagged with the Bug Humanitarian Award for folks who go out of their way to assist insects and other arthropods that are in imminent peril or who contribute in a positive way to habitat for the lower beasts.

You made my bug day!!!!  They call me Ellie Mae Clampett because I rescue everything whether its wants to be rescued or not!  LoL.
I’ll have the Corona with lime waiting on you!  Hehe


Letter 3 – Battered Imperial Moth


Mountain moth
Hellooooooo Bug folk. I was going to say “hello, buggers”, but caught myself when I remembered that this was a family channel. The rather poor picture below is of an enormous moth that I found in the mountain woods here in western North Carolina. It is at least as big as my hand, perhaps four by six inches. This picture is about life size. Finding this fellow was a Marlin Perkins, Marty Stouffer moment. I was out with my dogs and notice a flash of yellow to my right. I thought it was a swirling leaf but realized the leaf was swirling rhythmically. I walked over to see if it was a bird of some sort and when I got closer, saw that it was a huge moth lying on its back feebly flapping and twitching. I thought that I might turn it over so that it could fly off. When I did turn it over there on its back was one huge hornet and several smaller yellow jackets just stinging the poor thing. They would change position and sting. Move again and sting. The poor moth offered no resistance only flapping weakly. Now, I know I should have just left it alone, but it was too horrible to watch. My only weapon was the mail in my hand. And so I hit a home run with the large hornet ( with rage comes stupidity) but could not get the small ones to release. Ran back in to my house and got the wasp spray. Relocated the still flapping moth, got the yellow jackets off and forever gone. At end of the wasp war, the moth was not moving which was quite sad. So I went off to tend the dogs. When we returned I thought I would check on the poor moth victim. Amazingly it was walking about on the ground. Wings obviously damaged but still alive. When it saw me hovering, it climbed this pine tree. It is definitely the worse for wear and you can actually see the stinger marks on the wings. So, if you please, what is this moth? It is the palest yellow with visible circles and streaks in the palest cerise. Thank you so much. People really are grateful for this project you maintain. Oh, and by the way your site is entirely too “right-brained” in appearance and outlook to have been managed by just scientists. A big hurrah for the artists! Science can be art, too! P.S. The psychedelic caterpillars that evolved into the faithful beauty moth which you identified have not returned. You nailed it. In bird chat we would call it an accidental. But, we do have four more months of hurricane season…..
Kind regards, Enid Cheatham

Hi again Enid,
You are too funny. This is a very battered female Imperial Moth. We have some gorgeous images of more pristine specimens as well as many images of them mating.

Letter 4 – Bug of the Month January 2016: Imperial Moth Pupa


Subject: What is this??
Location: Myrtle Beach, South Carolina
December 12, 2015 2:05 pm
I dug up this bug in the dirt and I have no clue what it is and I have never seen it before. What is this?
Signature: Daniel

Imperial Moth Pupa
Imperial Moth Pupa

Dear Daniel,
This is a moth pupa, and we believe it is an Imperial Moth Pupa.  Many species of moths pass the winter as pupae, and many of those pupate underground.  The Imperial Moth Caterpillar dug beneath the surface of the soil to metamorphose, and in the spring the adult Imperial Moth will emerge.  Now that you have dug this individual up, you have to decide what to do to have it survive.  You can place it in a container with some loose dirt and keep it in a sheltered location that is unheated, like a screened porch or garage.  Hopefully your individual will survive the winter.  As we are preparing for a holiday trip, we are postdating submissions to go live while we are away, and we are tagging your submission as the Bug of the Month for January 2016 because we feel this is an appropriate species to represent the cold months of winter.

Letter 5 – CORRECTION: NOT Imperial Moth Lays Eggs


Imperial moths
I love your site and have used it often finding out the names of insects for my small Daycare. I found an Imperial moth this morning and put her into a butterfly cage we have and after some hours let her go so she wouldnt die. On a leaf in the cage are tiny yellow eggs so I guess she was doing more then we thought in there. I kept the eggs and would like to know some information on them. How long does it take for them to hatch? After hatching what do the little ones eat? How long before they will start to make cacoons? Thanks so much,
Karen Maier

NOT Imperial Moth Eggs with Caterpillars showing
(08/12/2007) Imperial moth eggs, me again w. photo
Have a great photo of the eggs I wrote you about acouple days ago. I couldnt believe I could actually see the little guys in there. Isnt it great. LOL I will take other pics as they grow but at this rate it probably wont be long before we have little ones running around.
Karen Maier

Hi Karen,
Feed them leaves from a wide variety of trees including Bald Cypress, basswood, birch, cedar, elm, hickory, Honeylocust, maple, oak, pine, Sassafras (Sassafras albidum), Sweetgum (Liquidambar styraciflua), sycamore, walnut. Visit BugGuide links for more info.

Hi Karen,
Thanks for sending in your photos of developing Imperial Moth Eggs. We eagerly await updates on the caterpillars progress.

NOT Imperial Moth Eggs Hatch
Well its only been about 4 hours since I took a photo of them and sent it. But checking on them at lunch time gave us a surprise, they were hatching. So I grabbed 4 or 5 different types of tree leaves to put in the cage. Do they need water?? or is the leaves enough. I really want the little guys to have a chance or turning into those beautiful Imperial moths.
Karen Maier
PS let me know if u want any more photos as they grow or if you have enough of that type. dont want to send any you cant use.

Hi Karen,
These are not Imperial Moth caterpillars. We fear you misidentified your original moth. BugGuide has an image of a newly hatched Imperial Moth, and it does not look at all like your caterpillars. We cannot identify your specimen from this hatchling image. We suspect this is still one of the Giant Silk Moths. If you describe the moth, we may be able to identify it. It would be great if you could take a photo at each stage of development, known as instars. Each time a caterpillar molts, there is a new instar. There are five instars before pupation. You caterpillars will fulfull their water needs through the leaves they eat. Thank you for noting in your photo title that the eggs hatched after four days.

Letter 6 – Definitely Imperial Moth Caterpillar


possible imperial moth caterpillar?
Hi Bugman!
My 9year old daughter found the caterpillar we have pictured here on either a mulberry or redbud tree here in central Indiana. We looked at your site and the Caterpillars of the Eastern Forest website and the closest we could come to picking a winner was the Imperial Moth caterpillar… could you confirm or deny? We would love to use this ‘pillar as a school project if we can figure out how to take care of it properly.
Many thanks!

Hi Kim,
You are absolutely correct in you identification. Continue to feed the caterpillar the leaves from the tree you found it eating.

Letter 7 – Female Imperial Moth


Giant moth?
November 22, 2009
This guy was resting on a wall in some woods I frequent for work in South Jersey. It was alive and did’nt seem to mind me taking photos of it. It was a decent six inches across and it was just impressive to see.
Tom Weightman
Haddonfield NJ

Imperial Moth
Imperial Moth

Hi Tom,
This gal is a female Imperial Moth, and she sure is a big specimen.

Imperial Moth
Imperial Moth

Letter 8 – Female Imperial Moth


Subject: Yellow moth
Location: SE Pennsylvania
August 6, 2014 6:02 am
My dog was “playing” with this moth this morning, so I moved it off the ground to where she couldn’t reach it. We’re in south east Pennsylvania, and its wingspan is roughly 4 inches. It has a “hairy” yellow head, and has a short, stout body about the circumference of one’s thumb. Any idea what it is?
Signature: Ron B.

Imperial Moth
Imperial Moth

Hi Ron B.,
This is a female Imperial Moth.  Females have more yellow while male Imperial Moths have more darker markings.  The sexual dimorphism is obvious when one is lucky enough to observe a mating pair of Imperial Moths.  Like other members of the Giant Silkmoth Family Saturniidae, Imperial Moths do not feed as adults as they do not have functional mouthparts.  They live long enough to mate and lay eggs.  Hopefully rescuing this gal from your dog will allow her to procreate.  For your kindness to one of the lower beasts, we are tagging this posting with the Bug Humanitarian Award.

Thank you, Daniel, for taking the time to help me know what kind of moth my dog found. She is doing fine resting high up on a fence post, waiting for the sun to go down. Thanks again…

Letter 9 – Female Imperial Moth


Subject: Imperial Moth
Location: Milford, Virginia
August 2, 2017 7:11 pm
I found this beautiful moth who was having a hard time staying in the air. I’ve been very careful with it, and my daughter has as well, not to touch his wings. Should I offer him anything to recoup before his relocation, and if so, what would that be?
Signature: Tiffany Poynor

Imperial Moth

Dear Tiffany,
This Imperial Moth looks to us like a female since her wings are mostly yellow.  Male Imperial Moths have more markings.  Often newly emerged Giant Silkmoths release some eggs prior to mating to enable them to fly better.  Imperial Moths do not eat or take any nourishment, so we would advise to you provide a sheltered location and let nature take its course.

You were so right. It laid an egg on her hand and started flying again. She’s been relocated to the barn. Thanks for the input.

Letter 10 – Female Imperial Moth


Subject: Lucky Nighttime find an Imperial!
Location: Near St. Louis, MO
August 9, 2017 11:09 pm
I found this beautiful female Imperial Moth. Absolutely stunning! She was having a hard time flying and was battering herself against a corner. I quickly scooped her up (got a few quick photos) and released her into our wooded area out back. I was even lucky enough to observe her warming up her wings! My question is…what is the large spot on the top of her head? It appeared to have less hair than the rest of her body.
Signature: Fayla

Female Imperial Moth

Dear Fayla,
The tattered wings on your female Imperial Moth indicates she has probably neared the end of her very short life.  The hairlike scales on her thorax have worn away which is revealing the exoskeleton, and that is the “spot” you noticed.  Because of your kindness, we are tagging your submission with the Bug Humanitarian Award.

Letter 11 – Female Imperial Moth from Costa Rica


Mystery Moth
May 17, 2010
Discovered this moth in a cane field next to an Arenal Volcana lava field in Costa Rica. It was dusk and raining. We were with a few others and no one had seen such a moth before, not even the local guide. It was a giant, about the size of a man’s hand. Very impressive.
Arenal Volcano area, Costa Rica

Female Imperial Moth from Costa Rica

Hi Paul,
This looks like a subspecies of our North American Imperial Moth.  We previously identified Eacles imperialis decoris in a different letter based on images on The World’s LArgest Saturniidae website and assistance from Bill Oehlke who wrote:  “It is Eacles imperialis decoris female, based on thin slightly scalloped pm line.”

Hi Daniel,
Many thanks for your quick response. I did check your website and do a google but failed to spot the moth, although I probably saw the other Imperials but then failed to make the connection. Thanks again.

Letter 12 – Female Imperial Moth laying eggs


Imperial Moth?? – Extreme South Georgia
Found this on my cypress fence this past week. Can’t find anything that states Imperial Moth come this far south. The eggs are still on the fence and there must be at least a dozen of them. Is it indeed an Imperial Moth???

Hi Cheryl,
Our Audubon Guide lists the range of the Imperial Moth as east of the Rocky Mountains from Canada to Mexico. Your specimen is within that range.

Letter 13 – First Imperial Moth sighting of the year


Subject: what kind of moth is this?
Location: Northwest Illinois
July 14, 2016 8:02 pm
Found this July 7th and July 14, 2016 live in NW IL near a fairly large lake ad wooded area.
Signature: Gary & Diane

Imperial Moth
Imperial Moth

Dear Gary & Diane,
This is our first Imperial Moth,
Eacles imperialis, posting of the year.  According to BugGuide:  “wings yellow, variably spotted and shaded with pinkish, orangish, or purplish-brown; male more heavily marked than female, especially in the south” which makes this a male Imperial Moth.

Letter 14 – Imperial Moth


Female imperial moth
Great website! A few years ago I came across this huge moth on the wall of a gas station along I-35. A bit raggedy, she is, but I thought the grey-blue wall of the store was a great contrast to her yellow!

Hi Jennifer,
We love your artful photo of an Imperial Moth.

Letter 15 – Imperial Moth


What type of moth
I live in Alabama. I found this moth on the ground and put him back on a tree he could not fly his abdomen was so large.
Greg W

Hi Greg,
Perhaps your female Imperial Moth, Eacles imperialis, was eggbound. Males have upper wings with mostly purple markings and the females are more yellow like your photo. Caterpillars feed on many types of trees including maple, oak, hickory and pine.

Letter 16 – Imperial Moth


My Granddaughter found this in the yard. I thought you could let us know what type of Moth it is and did it lay eggs. Thanks so much for your reply. Samantha is extremly interested in nature and loves to care for our garden, She is outstanding. I am her grandmother so I think she is the best. Thanks again for your time and interest in this matter. If you have any printed material can you send it to her. thanks again.
Her name is Samantha C. from lewes, delaware. again I thank you for looking at these pictures and finding out what she found and what it’s name is.
D. Smith

Hi D.,
Your granddaughter captured a female Imperial Moth, Eacles imperialis, formerly Basilona imperialis. Those are indeed eggs. When the eggs hatch, tell your granddaughter to feed the caterpillars fresh leaves from Oak, Hickory, or Maple. The moth, which does not feed as an adult, might already be dead. They only live a few days, long enough to mate and lay eggs. Male moths have more purple on the wings. Sorry, we have no printed material to send to Samantha, whose address we tactfully deleted.

Letter 17 – Imperial Moth


Photos . . .
Hi Everyone,
I really enjoy your website. I realize that you already have several examples of the Imperial Moth posted. However, I am attaching two photos I took a couple of days ago. My wife spied this beautiful creature asleep during the heat of the day in a small evergreen that sits right outside our bedroom window. She rushed into the house and had me grab the camera and take some shots. This moth has a wingspan nearly four inches and his markings and coloration are nearly impeccable. My family have really enjoyed these pictures and thought that others would like to see them as well. Hope you like them as much as we do. Sincerely,
Jim Green
Enterprise, Alabama

Hi Jim,
This is probably the best, most detailed image we have ever received of an Imperial Moth.

Letter 18 – Imperial Moth


I am sending you a picture of this rare moth, with a 6 inch wing span, We love to know more about this moth if you could help.

What a trophey specimen of an Imperial Moth.

Letter 19 – Imperial Moth


Hi Bugman,
This moth was rescued from a bucket of water in our backyard. We live in west central Illinois. We didn’t know how long she would be with us. So she stayed with us for 3 days, laying eggs each night. We released her so my 6 yr old,Madelynn, would have to perform a moth funeral. We left for 4 days to attend my Grandma’s funeral. Ok, so here is the next dilemma. Momma moth laid all these eggs, which have now started hatching (less than 2 weeks from momma’s arrival). I wasn’t really expecting hatchlings before we got home, if at all. Since we’ve gotten this far what should we do? Thought it might be fun to witness the complete cycle for a few, and release some too. Last summer it was 5 swallowtail butterflies. Madelynn swears her butterflies come back to play each year, because she has seen them and they know where we live! So hopefully you can understand this dilemma. Any help would be greatly appreciated! Thank You,
Sandy in Illinois

Hi Sandy,
Raising some of these Imperial Moth caterpillars, Eacles imperialis, to adulthood is something neither Madelynn nor you will ever forget. BugGuide includes the following as caterpillar food plants: “Larvae feed on leaves of Bald Cypress, basswood, birch, cedar, elm, hickory, Honeylocust, maple, oak, pine, Sassafras (Sassafras albidum ), Sweetgum (Liquidambar styraciflua ), sycamore, walnut. ” The caterpillars will feed on many deciduous and coniferous tree leaves, and you can search the internet for other lists that will include a tree that is available to you. Thanks for your wonderful letter.

Letter 20 – Imperial Moth


Large Moth-like bug!
Hello Bugman! My son found this out on our back deck this morning. I believe it looks like a large moth type insect. We live in east-central Indiana. Please help me to identify it and give me some other information on it! Thank You!
Megan and Kegan
Shirley, IN

Imperial Moth
Imperial Moth

Dear Megan and Kegan,
Your moth is an Imperial Moth, Eacles imperialis, a species well represented on BugGuide and in our own archives, though this is the first specimen we are posting this year.  Male Imperial Moths have more purple markings on their wings, and this would indicate that your individual is a male Imperial Moth.

Letter 21 – Imperial Moth


Is this an imperial moth?
Location: Huntingdon, Pennsylvania
July 23, 2011 1:42 am
Hello, this moth has been hanging around my back door this evening. Normally I can easily identify the strange giant moths on my door from pictures you have posted, but I’m not sure about this one. It is a greenish-brown sort of camouflage color. I tried to get as good of pictures as possible, but it was hard to get shots of its underbelly. Thanks!
Signature: Jess

Imperial Moth

Hi Jess,
Your identification of this Imperial Moth is absolutely correct.  She is a female.  Males have more purple markings on the wings.

Letter 22 – Imperial MOth


Subject: Imperial Moth
Location: NorthWest NJ
June 14, 2013 6:55 am
Hi, I found this amazing moth today, Friday, June 14, 2013 @ 8:07 a.m.. I believe it is an Imperial moth, are they common in NJ? It seems that his wings are very wet so he is unable to fly and it is a bit chilly out. Should I bring him indoors to dry out and warm up?
Signature: NikkiRu

Imperial MOth
Imperial MOth

Dear NikkiRu,
Was this shot in a cemetary?  We love your photograph, but we would recommend cropping it to include the top of the cross which would move the Imperial Moth out of the center of the frame.

Imperial Moth
Imperial Moth

Goid morning,
Actually both the cross and moth are in my backyard.  I will adjust the photo and resend later today for you.

Imperial MOth
Imperial MOth

Thanks Nicole.  We added the new photo to the posting.  We never responded to your question about taking the Imperial Moth indoors.  Especially since she is a female who is most likely releasing pheromones to attract a mate, taking her indoors might not be the best idea.

Letter 23 – Imperial Moth


Subject: not the main subject
Location: Jordan Lake NC
August 26, 2013 5:57 pm
Dear Bugman, I found the most beautiful Imperial Moth today..and I noticed while photographing the Moth, that a medium sized spider was tucked into a crack on the gas station wall. The back was ivory white..with some blackish design. I was very fortunate to see this Imperial…but the Spider was a nice extra treat!
Signature: Mary S

Imperial Moth
Imperial Moth

Hi Mary,
The dark markings indicate that this is a male Imperial Moth, and he is a lovely specimen.  Your spider is some species of Orbweaver.

Letter 24 – Imperial Moth


Subject: Imperial Moth
Location: St. Louis, MO
August 6, 2014 2:13 pm
I found a bug on the front door of a warehouse. I had planned on visiting your site for identification – the cover image happened to be the same critter.
Are these guys having a good year? I’ve never seen one before.
Signature: chrisv

Imperial Moth
Imperial Moth

Hi chrisv,
We cannot say that there are more Imperial Moth sightings than usual this year, though insect sightings do tend to be cyclical, with some years producing more individuals than other years.  This is the peak season for Giant Silk Moth sightings in North America, and each year we get numerous identification requests for members of the family Saturniidae in July and August, though sightings occur from spring through fall.

Letter 25 – Imperial Moth


Subject: imperial moth
Location: chesterton, Indiana
July 26, 2015 6:14 pm
This moth has black spots that remind me of mildew this a disease? Or something i should be concerned about. I have 3 acres of flower gardens and am afraid if its contageous in may lose all my butterfly and moths
Signature: kimmy t

Imperial Moth
Imperial Moth

Dear Kimmy,
This Imperial Moth looks perfectly normal to us and we do not believe you have to worry about it spreading a horrible plague to all your butterflies and moths.

Letter 26 – Imperial Moth


Subject: Moth
Location: Pa
August 5, 2016 9:06 pm
Large yellow moth-about 6″ across; in PA.
Signature: Tina

Imperial Moth
Imperial Moth

Dear Tina,
Judging by the size of the abdomen, this Imperial Moth is a female full of eggs.

Letter 27 – Imperial Moth


Subject: Moth
Location: Michigan
June 25, 2017 3:58 pm
What kind of moth is this?
Signature: Jaklynn

Imperial Moth

Dear Jaklynn,
Your moth is a female Imperial Moth,
Eacles imperialis.

Letter 28 – Imperial Moth and Preying Mantis


Subject: imperial moth? mantid?
Location: Central Texas
October 14, 2012 9:02 pm
I came across a recent posting of a male imperial moth that looked similar to a moth I found while at work a few years ago, I thought you might enjoy the juxtaposition in which the photo shows the moth… Also, I found this mantid at my house earlier today, In recent years I have seen a significantly larger number of mantids than in years past. I have no idea what this one was feeding on before I found him, but he was on the underside of our window on the outside of the house. It has currently been in the low to mid 80’s during the day, and was around 3p.m. when I saw him. I was wondering if you might possibly know what type of mantid he is?
Signature: curious?

Imperial Moth

Dear curious,
Thank you for sending your amusing Imperial Moth photo.  Preying Mantids are generally more visible in the fall because they have achieved maturity.  They are larger and more noticeable.  As with all insects, populations fluctuate from year to year.  Also, insects are easily overlooked.  Once one becomes more aware of insects, one tends to notice more.  Perhaps you are more aware of insects than you have been in past years.

Preying Mantis

Letter 29 – Imperial Moth by a Structuralist Insect Photographer


A few for your collection!
Hi there Bug People!
I like to photograph only the most taken for granted of things in the world…lowly mushrooms and fungus, insects, small rodents, amphibians, etc… I have included a few ( a very small sampling ) of my ‘insect world’ favorites for 2004. Hope you enjoy them! (Personally, I love the Imperial Moth that befriended my hand…the Stag is second place) All of these photos are from the location described below.
Kindest Regards,
Scott Pierson
Actual Location Data: (of all insect photos attached) Earleville, MD – in a small, private community named ‘Hazelmoor’.
Latitude: 39.4401 Longitude: -76.0247
Time is always (approx) between the hours of 20:30 to 00:00 hrs, EDT

My Goodness, Scott,
I admire the structuralist tendencies you have applied to your insect photographs. We agree that your Imperial Moth photo is amazing.

Thank you for your reply – I didn’t realize that you’d already posted it the website! My previous email did not include that “I think the site is great!” What a service to folks – especially those interested in insects. This is a great wealth of information and the fact that there are photos to examine is priceless. It’s great that you take the time to help folks out like this. Thank you again! Kindest Regards, Scott Pierson

Letter 30 – Bug of the Month September 2019: Imperial Moth Caterpillar


Subject:  LARGE green caterpillar
Geographic location of the bug:  Middle Georgia
Date: 08/28/2019
Time: 12:33 AM EDT
Your letter to the bugman:  This guy (girl?) showed up on my patio cover (canvas). It’s about 3 inches long and probably an inch around. (BIG joker). Thought maybe Luna Moth. Some one said maybe Imperial Moth. I know Lunas are endangered and I want to do the right thing. Don’t plan on hurting it or anything just curious about what it is.
How you want your letter signed:  Curious in GA

Imperial Moth Caterpillar

Dear Curious in GA,
This is an Imperial Moth Caterpillar.  Many Giant Silkmoth Caterpillars from the family Saturniidae and Hornworms from the family Sphingidae pass unnoticed on vegetation while they are feeding.  Fully grown caterpillars then hunt for a suitable place for pupation  They leave the food plant and at that time they are frequently discovered by observant humans.  When we receive images of pre-pupal Imperial Moth Caterpillars, they have frequently turned brown or orange as metamorphosis nears.  Your green individual might still be feeding

Letter 31 – Imperial Moth and Oakworm Moth


Subject: Floridian moths
Location: Southwest Florida
November 6, 2016 1:38 pm
Would you help me identify these two beauties?
The big yellow one, dying on its back, had similar coloring on the top side of its wings.
The reddish copper one, taking a nap on the wall, was much smaller.
Thank you!
Signature: Lost Yankee

Imperial Moth
Imperial Moth

Dear Lost Yankee,
Both of your moths are Giant Silkmoths in the family Saturniidae.  The dead yellow moth is an Imperial Moth,
Eacles imperialis, and in our opinion, they are much more beautiful alive than dead.  Though you did not indicate from where you were transplanted, you might be interested in knowing that the Imperial Moth is found throughout eastern North America, as far west as Texas and north into Canada.  Your other moth is an Oakworm Moth in the genus Anisota, and members of this genus share a similar range, but extending west to Arizona.

Oakworm Moth
Oakworm Moth

Neat! I wondered if the yellow one was
an Imperial. Certainly has a regally wide wingspan.  Maine is where I
come from, and even though the Imperial ranges that far north, I’ve never seen it.
Too bad the Oakworm moth caterpillars feed on our beautiful live oak trees, but they grow up to be good-looking little fuzzies.
Thank you very much for your quick and informative reply, Bugman! As I explore Florida, you may hear from me again.
Lost Yankee

Letter 32 – Caterpillar of Pine Imperial Moth


Subject: Unknown Butterfly Larvae
Location: Upstate New York
August 8, 2012 1:21 pm
It’s been around high seventies to eighties (Fahrenheit) up here for the past few days…this little one is about 4 inches long, and moves rather slowly. We found it on a concrete slab, and have no idea what it could be. All help would be appreciated, so we know what to feed the little fellow.*9
Signature: -Annika

Caterpillar of a Pine Imperial Moth

Dear Annika,
Thanks to your submission, we have learned an interesting bit of information.  We like to be able to cite sources when we provide responses, and rather than to just inform you that this is the caterpillar of an Imperial Moth, we turned to BugGuide where we learned that this is a subspecies known as the Pine Imperial Moth,
Eacles imperialis pini.  Here is how BugGuide differentiates the caterpillars of the two subspecies:  “Larva [Eacles imperialis pini]: abdominal segments have two rows (dorsal and dorsolateral) of large shiny white scoli (fleshy protuberances); spiracles white” while “nominate subspecies imperialis larva is larger (95-115 mm), dorsal and dorsolateral scoli much smaller or lacking, and spiracles usually yellow.”  BugGuide also indicates:  “larvae feed exclusively on conifers, mainly White Pine and Red Pine; also recorded on Jack Pine, Scotch Pine, and White Spruce” and based on the size and dark coloration of your individual, we suspect it has left its food source and is preparing to metamorphose into the pupal stage.  The caterpillar digs into the dirt when it is ready to pupate and the pupa is naked, not wrapped in a silken cocoon.  We don’t believe your caterpillar will be interested in eating since it is most likely preparing for pupation.  You can get additional information on Bill Oehlke’s Silkmoths website.


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17 Comments. Leave new

  • The mantis is an adult male Stagmomantis carolina.

  • Chris kratt172
    August 7, 2013 8:28 am

    I just caught a imperial moth, and I want her to lay eggs thought though I don’t know what to do in order to get her to lay them could you give me some advice?

  • I just found one of these on my front porch in New Orleans, LA! She dropped 2 eggs for us in her “habitat”. Is there any advice you can give me for helping the eggs to hatch?

    • Place them near a food source: “Larvae feed on leaves of Bald Cypress, basswood, birch, cedar, elm, hickory, Honeylocust, maple, oak, pine, Sassafras (Sassafras albidum), Sweetgum (Liquidambar styraciflua), sycamore, walnut” according to BugGuide.

  • I caught a female a minute ago, it let me catch it but it started vibrating(for body heat?) and took off, cool moth, really fuzzy.

  • Such an interesting bug! I have never seen it before either. After reading your post I immediately searched for more information in the internet. I think you should take care of it during the winter!

  • I found a female imperial today and while looking to find out what it was I found this site. She was awesome. I think the heat was getting to her because she was sitting on concrete. I took her in and she cooled down a few minutes so I took her back outside and she flew away. Sad to see her go but happy she is alive. Like you I rescue everything. My wife will not even tell me about a spider in the house anymore because I take them outside.

  • Hi, I have an imperial moth I would like to show, to see which one it is exactly. How do I post a picture here? Kind regards, Marieke

  • Scott Kinzler
    July 26, 2017 5:47 pm

    I found an Imperial Moth in Terre Haute, In today. 7/26/17

  • I found an imperial moth laying eggs in my gravel driveway. Should I move the eggs to a grassy area. They will surely get run over where they are. The mother looks like she’s about to die.

    • You can try moving them near a host tree. BugGuide lists food plants as “Larvae feed on leaves of Bald Cypress, basswood, birch, cedar, elm, hickory, Honeylocust, maple, oak, pine, Sassafras (Sassafras albidum), Sweetgum (Liquidambar styraciflua), sycamore, walnut.

  • is this bug poison

  • Emanuel Parker
    December 15, 2018 9:08 am

    I seen a moth look just like a king on the back in North Carolina can you tell me what kind of moth that is or was I just seeing things

  • Mary Jo Hobbs
    August 20, 2019 6:14 am

    After reading an earlier comment, I think I have a female imperial moth on the tree in front of my store. It was there yesterday and moved up the tree today and The tree might be a birch. I thought it was hurt and I was surprised with the size. Wingspan is as large as my iPhone. It is really beautiful. Let me know how I can send you a picture to confirm. Thank you

  • Is the face yellow and if touched does it sting? Asking because I accidentally rubbed a caterpillar today and got “stung” – trying to find it.


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