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Caterpillar Identification

Updated on January 6, 2017
Saddleback Caterpillar
Saddleback Caterpillar | Source

What Kind of Caterpillar Is This?

"Hey I found a caterpillar!" When I was young, we were always on the lookout for cool insects, especially cool caterpillars. Maybe you just found one and you're looking for a little help with identifying it. If so, you're are in the right place! I have been helping people ID specimens ever since I was a kid. I am always happy to have friends and neighbors bring me insects for identification. Most of the time it's something common yet cool, but once in a while I come across a real puzzler.

This article is intended to help you identify that caterpillar you found crawling across your kitchen floor, driveway, or on the side of your house.

White-Marked Tussock Moth

White-Marked Tussock Moth Caterpillar
White-Marked Tussock Moth Caterpillar | Source

This cool-looking species can be commonly found on trees in urban areas. They eat almost anything, including decorative hawthorns and acacias, and when they have a population explosion they can strip the leaves off of entire trees. White marked tussock moth caterpillars also have irritating spines that can cause a rash in some people, so handle with care!

The moth that these ones become is fairly plain, and the female doesn't even have wings—just a furry body which never really leaves the cocoon. The males fly to it, they mate, and the female lay a foamy mass of eggs right on the cocoon!

Woolly Bear

Woolly Bear Caterpillar
Woolly Bear Caterpillar | Source

This familiar orange and black caterpillar can often be found hustling across rural roads in late summer. They are a member of the Arctiidae family, which includes tiger moths and some of our most beautiful Lepidoptera. Wooly bears become the isabella tiger moth; the scientific name is Pyrrharctia isabella.

Wooly bears often hibernate over winter under a rock or in a sheltered place. When they spin a cocoon, it includes stiff bristles from their body. Handling a cocoon can give you little slivers, a little like handling fiberglass insulation.

Tomato Horn Worm

Tomato Horn Worm
Tomato Horn Worm | Source

The tomato hornworm is a familiar pest of tomato plants throughout North America. These big guys can completely destroy a tomato plant, and they eat both the leaves and the fruit. If something is eating the leaves of your plant down to the stem, and there are big holes being gnawed in the tomatoes, then these big green crawlers are probably to blame. Have a look around the base of the plant for big caterpillar poops—they look a little like hand grenades. If the poops are there, there's no doubt that you have tomato hornworms.

The best way to deal with them is to find them and pick them off by hand. Then you can drop them in a bucket of soapy water to kill them. You won't find every one, but you'll get enough to save your crop.

This cateprillar becomes a big, strong moth known as a hawkmoth. You can raise one or two to adulthood very easily if you're curious. Give them fresh tomato leaves and keep them in tupperware. They'll turn into a brown shiny pupae, then hatch into cool, big moths.

Polyphemus Moth

Polyphemus Caterpillar
Polyphemus Caterpillar | Source

I used to find these crawling on the side of my house. This big green caterpillar has silver strips on its side and red bumps along the body. It eats oak, maple, and willow. They can sometimes be found in late summer, wandering around looking for a place to pupate. They spin oval cocoons, sometimes under your house's eaves or in evergreens near the crop plants.

The adult moths are truly spectacular. They're various shades of soft brown, with a big smokey eyespot on each hindwing. The big single eye gives them their name, polyphemus, which refers to the one-eyed cyclops in The Odyssey.

Tiger Swallowtail

Tiger Swallowtail
Tiger Swallowtail | Source

This pretty green species with false eye-spots turns brown before it forms a chrysalis and turns into the tiger swallowtail, a truly spectacular butterfly with bold yellow and black stripes. I once found a number of these big beauties clustered around an outhouse—and they're also attracted to cigar smoke!

All of the swallowtail butterflies have a red forked organ called an osmeterium that can stick out from behind its head if it feels threatened. The osmeterium looks like a small snake tongue, which might scare off predators. It smells bad too. This defensive organ is unique to the swallowtails.

Black Swallowtail

Black Swallowtail
Black Swallowtail | Source

I have had these pretty green and black caterpillars on my carrots every year since I can remember. Like the above species, this swallowtail has an osmeterium as well. Sometimes known as a parsley worm, the black swallowtail caterpillar can eat a number of different umbelliferae species.

The black swallowtail butterfly is gorgeous, flying among gardens and forest edges in mid-summer. It's one of the most common swallowtail butterflies in North America.

Monarch Caterpillar

Monarch Caterpillar
Monarch Caterpillar | Source

One of the best known butterflies in North America, the monarch is famous for its astounding migration across half a continent during the winter to the piney mountains in Mexico. That feat is enough to make the monarch impressive, but there is more. The monarch caterpillar eats only milkweed plants, which have a toxic white sap that flows when a leaf or branch is broken, giving the plant its common name. It's thought that this species takes on the poison of the milkweed's leaves, which protects it from predators; since the big orange butterfly is toxic, other butterflies try to copy it. This is called mimicry and there are many species that look like the monarch for this reason.

Tersa Sphinx

Tersa Sphinx Caterpillar
Tersa Sphinx Caterpillar | Source

This cool looking caterpillar belongs to the sphinx moth group, which includes the tomato horn worm and many other big species. The false eyes on the head may scare away predators, and it acts like a small snake when threatened. The moths are sleek and streamlined, and look like a little jet plane.

Although this species is common only in the south, it has been spreading north recently, showing up as far north as Michigan and New York.

Imperial Moth

Imperial Moth Caterpillar
Imperial Moth Caterpillar

This caterpillar is huge. It eats maples and sycamores, and when it leaves the tree to look for a place to pupate, you may find it roaming around outside. Despite its horns and size, it's completely harmless.

The moth that this big crawler becomes, Eacles imperialis, is known as the imperial moth. It's mottled orange and yellow, and looks a lot like a big fallen leaf. This example of camouflage shows effective cryptic coloring.

Noctua Pronuba

Noctua pronuba Caterpillar
Noctua pronuba Caterpillar | Source

This species is a kind of cutworm, a group that feed on low plants, often eating through the stem near the ground and cutting down the plant like a lawn mower. Noctua pronuba was unknown in North America up until the 1970s, when it was introduced on the east coast. Within a few decades it had spread all the way across the continent, feeding on all kinds of plants.

This is a pretty moth that has quite a variety of colors—the forewings, or primaries, may be dark brown or light tan. The underwings are bright yellow which is how it got its name in Britain, "the large yellow underwing."

Rustic Sphinx

Sphinx rustica caterpillar
Sphinx rustica caterpillar | Source

Another large horn worm, Sphinx rustica has become quite common across the south and parts of the west. The caterpillar is gorgeous, but the moth is really cool-looking; big and thick-bodied, with rich rusty brown wings with black and white markings.

American Dagger Moth

American Dagger Moth Caterpillar
American Dagger Moth Caterpillar | Source

The American dagger moth is a member of a group, the Acronictinae, that has interesting caterpillars and fairly drab adult moths. Other members of this group, such as the funerary dagger moth, feature caterpillars that are truly weird looking. I always thought it odd that cool caterpillars have boring moths, but the pattern is often repeated across the Insect world.

Saddleback Cateprillar

Saddleback Caterpillar
Saddleback Caterpillar | Source

This one can sting, and I remember finding that out by accident when I was a boy. I handled one of these cool looking larvae, and wound up with a nasty, stinging rash. Saddlebacks belong to the Limacodidae family, which also includes other stinging specimens of various interesting designs.

These ones turn into a pretty brown moth with a variety of green and orange patches on the upper wings.

The Asp

The Asp Caterpillar
The Asp Caterpillar | Source

This is a stinging species that sometimes drops out of trees and onto people. The sting of the asp, which is also know as the puss caterpillar, can be quite severe. Pain can radiate into other limbs and can last for a day or more. These are more common in the south, where their appearance—and their stings—are often well known.

The Banded Sphinx

Banded Sphinx Caterpillar
Banded Sphinx Caterpillar | Source

This gorgeous specimen can be fairly common in Florida and other southern states, though this species is essentially tropical, ranging through the Caribbean and into Central and South America. It becomes a truly spectacular moth. This caterpillar is big and bright enough that people often find it on branches of their preferred food plant, water primrose.


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    • profile image

      Serra 2 days ago

      I picked up an orange and black fuzzy caterpillar, and it left yellow stuff on my hand. I can't find any websites that tell me what it is, but do you know?

    • profile image

      Brenda 2 days ago

      Found a shiny black caterpillar (?) Could have been a centipede.. ..with large orange spots...can't find anything like it ..wish I could send a pic...any idea what it could be?

    • profile image

      carlycat76 3 days ago

      I found a green hair less caterpillar and it has yellow slashes on it I piked it up and put it in my bug catcher any ides of what it eats or what kind of caterpillar it even is before it dies.

    • profile image

      Entomology is cool 11 days ago

      Maryalice BuschBacher, It is a swallowtail butterfly the spikes look dangerous but they are only to scare off predators. They love passion vine but are harmless and beautiful.

    • profile image

      Icearcticwolf 11 days ago

      i found the catipiller it has tiny thin strips little spikes and is't kind of greyish black.

    • profile image

      FCMosher 2 weeks ago

      @Lucas Katsuki -- thanks for your input -- tomato hornworms can have black or red horns. Determining these two species is hard but tomato hw more often have a kind of "V" as part of the white diagonal markings. So it's possible that the tomato hw pictured here is actually a tobacco hw, but it's not necessarily due to the red horn. Thanks again for your comment.

    • profile image

      Jennifer Montoya 2 weeks ago

      I found a caterpillar i need help identifying. Usually I can do it on my own but I'm having some difficulty with this one. Can I send in a picture?

    • profile image

      Cat 4 weeks ago

      I found a white hairless caterpillar in my drive way. It's a fat white with brown head. I never saw these before and would like to know what they are?

    • profile image

      AmyHollenbach 6 weeks ago

      Wondering what kind of worm I found. Can we post pics? Thought it was a cocoon at first but then I saw legs with green body underneath. Back had white string like projections that would move freely if you blew on them. Found on black walnut tree leaf.

    • profile image

      Rocky Wright 2 months ago

      I was about to play with my dogs and i was about to use my dogs toy tire when i noticed a black body with dark orangish spines with a white stripe on its back i was making sure it wasnt poisoness so i got it out and didnt touch it. Look me up on facebook or instagram rocky_hnhs_2021 thanks.

    • profile image

      Lucas Katsuki 2 months ago

      Your "tomato hornworm" is actually a tobacco hornworm, hence the red horn.

    • profile image

      Brad 2 months ago

      Found a huge green cat on a pecan tree it has black thornes that almost circle each section of his body... he has a big white spotch above his head with two big black spots an the horns around that area start out orange an end black it makes the tomato horn worm look like a inch worm. Any ideas...

    • profile image

      Elaine 2 months ago

      Found 3 caterpillars on my fern.

      Black and fuzzy with tiny yellow stripes down each side. Need help identifying what kind it is.

    • profile image

      Jasmin and vanessa 2 months ago

      I found a brown and blackish caterpillar like noctua pronuba but smaller found him on my carpet

    • profile image

      Sharon 2 months ago

      Yesterday I was sitting under a tree when a caterpillar type thing fell on my husband. I took a picture of it. It is a rusty color very hairy long snout and appears to have 2 white eyes and dragon like or aligator type spikes across its back. What is this and was it poision.

    • profile image

      Henry 2 months ago

      Hey my mom was cutting grass and she found a black caterpillar with yellow bands, and it was also horned. I couldn't find its species, so I just wanted to ask if you knew any kind of caterpillar that looked like that.

    • profile image

      Maryalice Buschbacher 2 months ago

      I would like to know what kind of

      Caterpillar I have found. Dark brown with orangish spikes. They have eaten my entire Dutch Passion Vine here on Fort Myers Beach. Thanks

    • profile image

      Girl 2 months ago

      I found a caterpillar and it has a green body brown head and no spikes or hair or anything like that any suggestions?

    • fcmosher profile image
      Author

      FCM 3 months ago from near the Equator

      Hi I think this is the caterpillar of Abbott's sphinx moth. There are two color morphs, one green/black and the other brown as you describe. Try an image search and see if it fits.

    • profile image

      Pam Hunter 3 months ago

      Trying to identify a caterpillar found on a virginia creeper vine in Manitoba, Canada. The closest on this website the Texas Sphinx but it says it is not found this far north.

      Who am I?...

      ..brown with a beige strip along the sides nearer the top of it's body

      ..no hairs

      ..tiny white legs

      ..little black protrusion on top of head/tail - looks like a shiny bead

      ..long and fat as my index finger

      ..actually what looks like head seems to be tail as it "searches" with the other end

      ..snake like face/tail

      ..acts like a snake - rears to strike

    • profile image

      baarbara 4 months ago

      The caterpillar I have on my sage plant is a small 1 inch to 1 1/2 inchs, banded yellow and black, thin body, black spines from the black bands. I cannot find what it is and if it harmful or good.

    • profile image

      Hhh 4 months ago

      I've found a red/orange caterpillar at with antenna and knobs, along with retractable yellow/orange horns, any ideas?

    • profile image

      WEARAnglers 7 months ago

      Our poor Bollock.

      R.I.P Mate!

      Gone but never forgotten, well atleast by R0b and Ty0m and the guys from work experience

    • profile image

      bella 2 years ago

      I found this bug but it looks like a caterpillar. it has a orange body with yellow dots on its side and its about three inches long.I found it on my driveway on a fall day in Virginia.

    • Pamela Kinnaird W profile image

      Pamela Kinnaird W 3 years ago from Maui and Arizona

      Oh my, you are a brave soul -- looking at all these photos of these caterpillars and studying them. The one hub I did on a caterpillar will be my last. But these ones you have put together in this hub are really amazing -- for the brave of heart. I'm going to post this on my insect board at Pinterest. Voting way up and Sharing.

    • Kimberly Vaughn profile image

      Kimberly Vaughn 4 years ago from Midwest

      This is so cool! I've never seen caterpillars so close before.