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North American Caterpillar Identification

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The caterpillar of the beautiful garden tiger moth

The caterpillar of the beautiful garden tiger moth

A Guide to Common North American Caterpillars

This guide to the more common caterpillars of North America is for gardeners, students, and anyone who has an interest in the natural world. Almost everyone will come across a caterpillar at one time or another; this guide helps you identify the most commonly encountered species.

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 guide is a bit of what I have learned over the years about caterpillars, and about insects in general.

Note: The following sizes and descriptions refer to full-grown larvae. Caterpillars molt up to five times before pupation, and they appear different at each stage (or instar). Interestingly, larvae don't simply shed their skins (like snakes do). They digest and reabsorb most of it.

Caterpillars In This Guide

25 of the Most Common Caterpillars in North America

  1. Banded Woollybear (13 fuzzy segments in a black-orange-black pattern)
  2. Tomato Hornworm (large and green, with seven white, V-shaped stripes on each side and a dark blue-black horn)
  3. Polyphemus Moth (large and green, with yellow stripes and red and orange bumps on each segment)
  4. Eastern Tiger Swallowtail (green, with two false eyespots and well-defined segments)
  5. Giant Swallowtail (could be easily mistaken for bird poop)
  6. Black Swallowtail (black and green bands punctuated by yellow dots)
  7. Monarch Caterpillar (green, black, and yellow stripes, and two black antennae on each end)
  8. Tersa Sphinx (green or brown with two large eyespots near the head capsule followed by a line of smaller eyespots)
  9. Imperial Moth (large, spiky, and hairy, with yellow horns and two black-ringed white spots per segment)
  10. Noctua Pronuba (green or brown with a row of black marks on the dorsal region)
  11. Rustic Sphinx (bright green with a textured horn and diagonal yellow stripes outlined in purplish black or dark green)
  12. Banded Sphinx (green, yellow, or reddish pink with white-rimmed black spots and diagonal white stripes)
  13. Southern Flannel Moth (V)* (hairy caterpillars with long tails and no visible segments)
  14. White-Marked Tussock Moth (V) (hairy, with a red head and four tufts of white, grey, or yellow hair on their first four abdominal segments)
  15. American Dagger Moth (V) (white and fluffy, with long black tufts of hair on their backs)
  16. Saddleback Caterpillar (V) (bright green "saddle" and prickly spines protruding from various points along the body)
  17. European Gypsy Moth (V) (hairy, with five pairs of blue dots and six pairs of red dots along their backs)
  18. Western Tent Caterpillar (A)** (hairy, with a pale blue head and a stripe of whitish-blue dashes (one per segment) along its back)
  19. Eastern Tent Caterpillar (A) (hairy, with a solid white stripe down its back and blue-patterned stripes on each side)
  20. Fall Webworm (A) (hairy and white, with black or orange heads and warts)
  21. Azalea Caterpillar (A) (black and hairy, with eight broken stripes (white or yellow) running parallel along their bodies and red legs and head capsules)
  22. Yellownecked Caterpillar (A) (black and hairy, with continuous yellow stripes, orange feet, and a yellow or orange band behind the head capsule)
  23. Contracted Datana Caterpillar (A) (hairy, with a large, black dorsal stripe and four whitish-cream and three black stripes on each side)
  24. Walnut Caterpillar (A) (black, with whitish-grey hairs protruding in rings from each segment)
  25. Garden Tiger Moth Caterpillar (very furry, with black, orange, and white hairs mixed in)

*(V) = venomous

**(A) = may cause an allergic reaction

Continue scrolling for detailed descriptions and photos of these caterpillars! To see what some of these caterpillars look like when they turn into moths or butterflies, check out this guide!

Woolly Bear Caterpillar

Woolly Bear Caterpillar

1. Banded Woollybear

Scientific Name: Pyrrharctia isabella

Size: 5.7 cm

Hosts: many hosts, including herbs, birches, clover, corn, dandelions, elms, maples, grass, and sunflowers

Range: throughout the USA and southern Canada

These cats are a member of the Arctiidae family, which includes tiger moths and some of our most beautiful Lepidoptera. Woollybears become the Isabella tiger moth.

How to Identify a Woolybear

Woollybears are quite easy to identify. They have a black-orange-black pattern, though the width of the bands varies. They also have a distinctly fuzzy appearance, thought their bristles are actually quite hard.

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This familiar orange and black caterpillar can often be found hustling across rural roads in late summer. Woollybears often hibernate during winter under a rock or in a sheltered place. When they spin a cocoon, it includes the stiff bristles from their body. This makes handling the cocoon tricky, and can leave you with tiny hairs stuck in your skin, like fiberglass insulation or some kinds of cactus. Not fun!

Note: While some people report handling these cats and their cocoons without any issues, touching banded woolybears will often result in a hand full of little slivers, a little like what you might get from handling fiberglass insulation.

Tomato Hornworm (note the blue horn)

Tomato Hornworm (note the blue horn)

2. Tomato Hornworms

Scientific Name: Manduca quinquemaculata

Size: 10 cm

Hosts: plants in the nightshade family (Solanaceae), including potato, tobacco, and tomato

Range: Northern Mexico, most of the United States, and occasionally southern Canada. Uncommon in the Southeast and the Great Plains.

This caterpillar 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 brown shiny pupae, then hatch into cool, big moths.

How to Identify a Tomato Hornworm

Tomato hornworms are often mistaken for tobacco hornworms (Manduca sexta). The two look remarkably similar, and it can be very difficult to tell them apart. To make matters worse, the internet is completely unreliable on this subject, and the photos are very commonly mislabeled.

The best way to distinguish the two is to look at their stripes. The tomato hornworm has seven white stripes bordered in green, and its horn is blue. The tobacco hornworm, on the other hand, has six white stripes bordered in black, and its horn is red. Below are photos of both types of hornworm.

Tobacco Hornworm (note the red horn and the black-banded stripes)

Tobacco Hornworm (note the red horn and the black-banded stripes)

How to Get Rid of Hornworms

Both types of hornworm are familiar pests throughout North America. These big guys can completely destroy a tomato or tobacco plant (not to mention many other kinds of plants), 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 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.

Polyphemus Caterpillar

Polyphemus Caterpillar

3. Polyphemus Moth

Scientific Name: Antheraea polyphemus

Size: 7 cm

Hosts: A wide variety of trees and shrubs including oak, willow, maple, and birch

Range: Canada (except Newfoundland and Prince Edward Island), the United States (every state except Arizona and Nevada), and Mexico

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.

How to Identify Polyphemus Moth Caterpillars

This big, green caterpillar has yellow stripes punctuated by red and orange bumps on each well-defined segment.

I used to find these crawling on the side of my house. 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.

Eastern Tiger Swallowtail immediately before pupation.

Eastern Tiger Swallowtail immediately before pupation.

4. Eastern Tiger Swallowtail

Scientific Name: Papilio glaucus

Size: 5.5 cm

Hosts: Leaves from plants including wild cherry, sweetbay (Magnolia), basswood, tulip tree, birch, ash, cottonwood, mountain ash, and willow

Range: eastern North America from Ontario south to the Gulf coast and west to the Colorado plains and central Texas

This pretty green species 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. They're also attracted to cigar smoke!

How to Identify Eastern Tiger Swallowtail Caterpillars

Mature larvae are green and have two false eyespots on their thoraxes. Fully grown caterpillars turn brown before pupation (i.e. immediately before forming a chrysalis).

All swallowtail caterpillars have a red or yellow forked organ behind their heads called an osmeterium. While it is normally hidden, caterpillars can evert (push out) their osmeteria if they feel 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.

The gorgeous tiger swallowtail butterfly

The gorgeous tiger swallowtail butterfly

caterpillar-identification

5. Giant Swallowtail

Scientific Name: Papilio cresphontes

Size: 6 cm

Hosts: Citrus, especially orange and lemon trees

Range: eastern North America from Wisconsin south to the Gulf coast and west to the Colorado plains and central Texas

How to Identify Giant Swallowtail Caterpillars

These cool caterpillars look a lot like bird poop, which may deter or fool birs and other predators. If that fails, they can deploy their osmeterium, a gland behind the head that pops out and looks like a snake's tongue. Special bonus: it also smells like rotting fruit!

Black Swallowtail Larva

Black Swallowtail Larva

6. Black Swallowtail

Scientific Name: Papilio polyxenes

Size: 5 cm

Hosts: leaves of a number of different umbelliferous species, including Queen Anne's Lace, carrot, celery, and dill; and plants in the citrus family (Rutaceae)

Range: most of the eastern USA, north into Quebec, west into southern Saskatchewan, Colorado and southeastern California, and south to northern South America

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.

How to Identify Black Swallowtail Caterpillars

I have had these pretty green-and-black caterpillars—sometimes known as parsley worms—on my carrots every year since I can remember. They can be identified by their distinctive black and green bands, which are punctuated by yellow dots. Like the above species, this swallowtail has an osmeterium as well.

The Black Swallowtail

The Black Swallowtail

Monarch Caterpillar

Monarch Caterpillar

7. Monarch Caterpillar

Scientific Name: Danaus plexippus

Size: 2.5–4.5 cm

Hosts: Milkweeds! (Interestingly, adult Monarch butterflies feed on milkweed nectar, so the food source for Monarch butterflies and their larvae is nearly identical.)

Range: Southern Canada through the USA, Central America, and most of South America. Also present in Australia, Hawaii, and some Pacific Islands.

One of the best-known butterflies in North America, the monarch is famous for its astounding winter migration across half a continent to the piney mountains in Mexico. That feat is enough to make the monarch impressive, but there is more.

How to Identify Monarch Caterpillars

Monarch caterpillars sport many narrow bands of black, yellow, green, and white. They also have four distinctive 'antennae,' two on each end.

Why Do Monarch Caterpillars Eat Milkweed?

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.

The Monarch

The Monarch

Tersa Sphinx Caterpillar

Tersa Sphinx Caterpillar

8. Tersa Sphinx

Scientific Name: Xylophanes tersa

Size: 10 cm

Hosts: smooth buttonplant, starclusters, Borreria, Catalpa, and Manettia

Range: From Massachusetts south to Florida and west to Nebraska, New Mexico, and southern Arizona. Also present in Mexico, the West Indies, Central America, and Argentina.

This cool-looking caterpillar belongs to the sphinx moth group, which includes the tomato hornworm 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.

How to Identify Tersa Sphinx Caterpillars

These caterpillars can be either green, black, or brown, though all have two large false eyespots near the front of their heads followed by smaller eyespots in lines down their bodies. These eyes follow a whitish line that runs the length of their bodies and spreads downwards in diagonal slashes.

Imperial Moth Larva

Imperial Moth Larva

9. Imperial Moth

Scientific Name: Eacles imperialis

Size: 7.5–10 cm

Hosts: conifers and deciduous trees and shrubs including pine, oak, sycamore, maples, sweet gum, and sassafras

Range: from Maine west to eastern Nebraska and south to the Florida Keys and central Texas

This caterpillar is huge (one of the largest in North America!). 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.

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—an example of effective cryptic coloring.

How to Identify Imperial Moth Caterpillars

This spiky caterpillar has yellow horns and two black-ringed white spots per segment (one on each side of its body). These cats can be either brown or green.

Note: Despite its horns and size, it's completely harmless.

Noctua Pronuba Larva

Noctua Pronuba Larva

10. Noctua Pronuba

Scientific Name: Noctua pronuba

Size: 4.5 cm

Hosts: weedy and cultivated plants, including cherry tomatoes, beets, and grapes

Range: native to Eurasia and Africa, but were accidentally introduced to Nova Scotia in 1979 and have since spread to Alaska, California, and British Columbia

This species is a kind of cutworm, a group that feeds on low plants, often eating through the stem near the ground and cutting down the plant like a lawnmower. Noctua pronuba was unknown in North America 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."

How to Identify Noctua Pronuba Larvae

These cats come in various shades of green and brown and can be identified by the row of black marks on their dorsal region.

Rustic Sphinx Larva

Rustic Sphinx Larva

11. Rustic Sphinx

Scientific Name: Manduca rustica

Size: 9 cm

Hosts: fringe tree and jasmine, bushy matgrass, knockaway, and Bignonia species

Range: From Virginia to south Florida and west to Arkansas, Texas, southern New Mexico, Arizona, and southern California. South through Central America to Uruguay. Occasionally present in Maine, Massachusetts, and New York.

Another large hornworm, 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 too—big and thick-bodied, with rich, rusty brown wings and black and white markings.

How to Identify Rustic Sphinx Larvae

These bright green cats have diagonal yellow stripes outlined in purplish-black or dark green. They also sport the typical hornworm horn, though unlike other hornworm species, theirs has a granulated texture. In their final cat stage, their dorsal surfaces turn a reddish-brown color.

Sphinx rustica caterpillar

Sphinx rustica caterpillar

Banded Sphinx Larva

Banded Sphinx Larva

12. The Banded Sphinx

Scientific Name: Eumorpha fasciatus

Size: 7.5 cm

Hosts: plants in the evening primrose family

Range: From northern Argentina through Central America and Mexico to southern California and southern Arizona, and from southern Arizona east to Texas, Mississippi, Florida, and South Carolina. Occasionally present in Missouri, Michigan, Pennsylvania, New York, and Nova Scotia.

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.

How to Identify Banded Sphinx Caterpillars

The appearance of these cats is quite varied, from mostly green to yellowy with pink and black cross-stripes, red feet, and red-edged green stripes. Their most common features are white-rimmed black spiracles (they look almost like tiny eyes) and diagonal white stripes.

Banded Sphinx Caterpillar

Banded Sphinx Caterpillar

13. Southern Flannel Moth (a.k.a. The Asp)

Scientific Name: Megalopyge opercularis

Size: 3.5–4 cm

Hosts: shrubs and trees, including almond, apple, hackberry, oak, orange, pecan, persimmon, and rose

Range: From Maryland to Florida and west to Missouri and Texas. Occasionally present in New York and Pennsylvania.

This stinging species sometimes drops out of trees and onto people. The sting of the asp, which is also known 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.

How to Identify a Southern Flannel Moth Caterpillar

Asps come in many colors, from grey-flecked black and golden brown to fiery orange. It often has a bright orange streak running along its side. Their bodies taper into a long tail. Young larvae may have very curly hair, giving them a fluffy look.

Asp Caterpillar

Asp Caterpillar

What to Do If You're Stung by a Puss Caterpillar

While being stung by a puss caterpillar is incredibly painful, it won't kill you, so don't panic. This procedure applies to the asp as well as all other stinging caterpillars!

  1. Place tape (any kind works, but Scotch or duct tape are ideal) sticky side down on the affected area and pull it off to remove the spines. Repeat until spines are gone.
  2. Apply ice packs to the affected area.
  3. Make a paste with baking soda and water, and apply it to the affected area.

Note: If you have a history of asthma, hay fever, or allergies, or if you develop an allergic reaction after being stung, call your doctor immediately.

The Asp Caterpillar

The Asp Caterpillar

White-Marked Tussock Moth Caterpillar

White-Marked Tussock Moth Caterpillar

14. White-Marked Tussock Moth

Scientific Name: Orgyia leucostigma

Size: 3.5 cm

Hosts: more than 140 known hosts, including apple, alder, birches, balsam fir, and larch

Range: Eastern North America

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.

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 the female, they mate, and the female lays a foamy mass of eggs right on the cocoon!

How to Identify White-Marked Tussock Moth Caterpillars

These cats are known for their distinct red head (with two hairy 'antennae') and four tufts of hair (either white, grey, or yellow) on their first four abdominal segments. They have a broad black stripe along their back, with yellow stripes on either side, and two red glands towards the end of their abdomen. They have many other tufts of hair near their legs and abdomen.

Note: White-marked tussock moth caterpillars also have irritating spines that can cause a rash in some people, so handle with care!

American Dagger Moth Caterpillar

American Dagger Moth Caterpillar

15. American Dagger Moth

Scientific Name: Acronicta americana

Size: 5 cm

Hosts: various trees, including alder, ash, birch, elm, hickory, maple, oak, poplar, walnut, and willow

Range: Eastern North America

The American dagger moth is a member of the vrey large genus Acronicta, a group 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 make "boring" moths, but the pattern is often repeated across the insect world.

How to Identify American Dagger Moth Caterpillars

These fluffy, white caterpillars are characterized by several long, black tufts (or setae) on their back. These setae are what can cause an allergic reaction in some people.