North American Caterpillar Identification
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.
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.
24 of the Most Common Caterpillars in North America
- Banded Woolybear (13 fuzzy segments in a black-orange-black pattern)
- Tomato Hornworm (large and green, with seven white, V-shaped stripes on each side and a dark blue-black horn)
- Polyphemus Moth (large and green, with yellow stripes and red and orange bumps on each segment)
- Eastern Tiger Swallowtail (green, with two false eyespots and well-defined segments)
- Black Swallowtail (black and green bands punctuated by yellow dots)
- Monarch Caterpillar (green, black, and yellow stripes, and two black antennae on each end)
- Tersa Sphinx (green or brown with two large eyespots near the head capsule followed by a line of smaller eyespots)
- Imperial Moth (large, spiky, and hairy, with yellow horns and two black-ringed white spots per segment)
- Noctua Pronuba (green or brown with a row of black marks on the dorsal region)
- Rustic Sphinx (bright green with a textured horn and diagonal yellow stripes outlined in purplish black or dark green)
- Banded Sphinx (green, yellow, or reddish pink with white-rimmed black spots and diagonal white stripes)
- Southern Flannel Moth (V)* (hairy caterpillars with long tails and no visible segments)
- 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)
- American Dagger Moth (V) (white and fluffy, with long black tufts of hair on their backs)
- Saddleback Caterpillar (V) (bright green "saddle" and prickly spines protruding from various points along the body)
- European Gypsy Moth (V) (hairy, with five pairs of blue dots and six pairs of red dots along their backs)
- Western Tent Caterpillar (A)** (hairy, with a pale blue head and a stripe of whitish-blue dashes (one per segment) along its back)
- Eastern Tent Caterpillar (A) (hairy, with a solid white stripe down its back and blue-patterned stripes on each side)
- Forest Tent Caterpillar Moth (A) (hairy, with a line of footprint-shaped white marks along its back and orange and blue stripes on either side)
- Fall Webworm (A) (hairy and white, with black or orange heads and warts)
- Azalea Caterpillar (A) (black and hairy, with eight broken stripes (white or yellow) running parallel along their bodies and red legs and head capsules)
- Yellownecked Caterpillar (A) (black and hairy, with continuous yellow stripes, orange feet, and a yellow or orange band behind the head capsule)
- Contracted Datana Caterpillar (A) (hairy, with a large, black dorsal stripe and four whitish-cream and three black stripes on each side)
- Walnut Caterpillar (A) (black, with whitish-grey hairs protruding in rings from each segment)
*(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!
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. Woolybears become the Isabella tiger moth.
How to Identify a Woolybear
Woolybears are quite easy to identify. They have 13 distinct segments in 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.
This familiar orange and black caterpillar can often be found hustling across rural roads in late summer. Woolybears 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.
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.
The Next Punxsutawney Phil?
Legend has it that the width of a woolybear's orange stripe signals the severity of the winter to come. Supposedly, a wide band indicates a mild winter, whereas a narrow band indicates a harsh one.
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.
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.
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
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!
This cute caterpillar was the inspiration for the Pokémon Caterpie.
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, 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.
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.
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.
Climate change and human interference are causing a decline in Monarch butterfly populations. We must do what we can to protect and conserve their wintering sites in California and Mexico, migration corridors, and main breeding areas.
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.
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.
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.
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.
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.
Some scary-looking caterpillars are completely harmless, while others that look fluffy and sweet will leave you with a nasty rash. It's usually safest not to touch caterpillars at all (which is better for the caterpillar, too!), but these are the ones you really want to avoid.
Southern Flannel Moth (a.k.a. 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.
The asp is a the top of this list for a reason—however soft and sweet these little guys might look, their stings can be severe enough to require hospitalization. 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.
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!
- 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.
- Apply ice packs to the affected area.
- 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.
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
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 Acronictinae, 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.
Scientific Name: Acharia stimulea
Size: 2.5 cm
Hosts: many plants, including aster, blueberry, citrus, corn, dogwood, elm, grape, linden, maple, oak, and sunflower
Range: from Massachusetts to Florida and west to eastern Missouri and Texas
This one can sting, as I found 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.
How to Identify Saddleback Caterpillars
These cats are hard to miss! They sport LOTS of poisonous spines, the largest of which project from the head and abdomen. The "saddle" refers to the green patch on this larva's back, which has a large, purple-brown spot in the center.
European Gypsy Moth
Scientific Name: Lymantria dispar dispar
Size: 4–5 cm
Hosts: hardwood trees, including apple, oak, poplar, alder, willow, hawthorn
Range: Native to Europe and Asia, this species has since spread to North America. They are present from New England west to Michigan and south to Virginia, as well as from California north to British Columbia.
How to Identify European Gypsy Moth Caterpillars
Though these cats are often confused for tent caterpillars, they are easy to identify because of the distinctive pairs of blue and red dots (five and six pairs, respectively) that run down their backs. They don't make webs ("tents"), either.
Western Tent Caterpillar
Scientific Name: Malacosoma californicum
Size: 4.5–5 cm
Hosts: a range of tree and shrub species, including aspen, willow, crabapple, poplar, and mahogany
Range: from southeastern Canada to New York and west to the Pacific Coast
How to Identify Western Tent Caterpillars
These cats are extremely variable in appearance, which can make them challenging to identify. Most mature larvae have a pale blue head followed by a stripe of whitish blue dashes (one per segment) that runs along their back. This stripe is outlined on either side by black-bordered bands of black or orange, below which tufts of white-tipped orange hairs run the length of their bodies.
Eastern Tent Caterpillar
Scientific Name: Malacosoma americanum
Size: 5.7 cm
Hosts: trees belonging to the rose family, such as apple, cherry, and crabapples
Range: from central eastern USA up to the Rockies, and Canada from Nova Scotia to Alberta
How to Identify Eastern Tent Caterpillars
These larvae have blue-patterned stripes running along each side and a solid white stripe running down the center of their back. Tufts of hair (ranging from whitish to orangey-brown) run below the blue stripes on both sides.
Forest Tent Caterpillar Moth
Scientific Name: Malacosoma disstria
Size: 4.5 cm long
Hosts: oak, gum, basswood, plum, and trembling aspen (depending on the region)
Range: present throughout most of the USA and southern Canada
How to Identify Forest Tent Caterpillar Moth Larvae
The Forest Tent Caterpillar is often confused for the Eastern Tent Caterpillar, but an easy way to distinguish the two is to look at the markings on their backs. Whereas the Eastern species has a solid white stripe along its back, the Forest species has a line of footprint-shaped white marks instead.
Scientific Name: Hyphantria cunea
Size: 2.5 cm
Hosts: close to 90 of species of deciduous trees, including, walnut, cherry, and crabapple
Range: present throughout the USA and in southern Canada
How to Identify Fall Webworms
Fully-grown larvae are covered in whitish hairs that protrude from pairs of warts along their backs. In northern regions, these warts are black, as is the head capsule, whereas both the warts and head capsule are orange in southern regions.
Scientific Name: Datana major
Size: 5 cm long
Range: from Nova Scotia to Florida and west to Kansas and Arkansas
How to Identify Azalea Caterpillars
If your dwindling crop of azaleas isn't clue enough, these cats are easy to identify (though they do look strikingly similar to the next caterpillar on this list). Their base color is black, with eight broken stripes (either white, yellow, or somewhere in between) running parallel down their bodies. Their legs and head are red, and sparse tufts of feathery white hair protrude from their sides.
Scientific Name: Datana ministra
Size: 5 cm long
Hosts: many trees, such as birches, elms, maples, and apple
Range: throughout the eastern United States
How to Identify Yellownecked Caterpillars
This cat, while quite visually similar to Datana major, can be distinguished by several distinct features. It differs from the latter in the following ways. It sports a yellow or orange band behind its head, and while the Azalea Caterpillar's stripes are broken, those of the Yellowneck are not. Its feet are also orange rather than red.
When threatened, Azalea and Yellownecked Caterpillars will stand on their abdominal prolegs and raise both ends of their bodies until they nearly touch.
Contracted Datana Caterpillar
Scientific Name: Datana contracta
Size: 5 cm long
Hosts: trees, such as sycamores, chestnuts, and oaks
Range: from Maine south to Florida and west to Arkansas and Wisconsin
How to Identify Contracted Datana Caterpillars
These cats look quite similar to Yellownecked Caterpillars, but they can be distinguished by their stripes. Contracted Datana Caterpillars have a large black stripe along the center of their backs, with four whitish-cream and three black stripes on each side.
Scientific Name: Datana integerrima
Size: 5 cm long
Hosts: leaves of trees in the walnut family, such as walnut, hickory, and pecan
Range: From Minnesota to Texas and Quebec to Florida. Also present in Arizona.
How to Identify Walnut Caterpillars
These caterpillars have black bodies with whitish-grey hairs that protrude in rings from each segment.
- Gypsy Moth Identification
- Walnut Caterpillar
- Yellownecked Caterpillar
- Azalea Caterpillar - Datana major
- Forest Tent Caterpillar - Malacosoma disstria
- Fall Webworm
- Western Tent Caterpillar
- Gypsy Moths
- Banded sphinx - Eumorpha fasciatus
- Puss Caterpillar - Megalopyge opercularis
- American Dagger Moth - Acronicta americana
- Rustic Sphinx - Manduca rustica
- Large Yellow Underwing moth and cutworm caterpillar
- Imperial Moth - Eacles imperialis
- Tersa Sphinx - Xylophanes tersa
- Monarch - Danaus plexippus
- Black Swallowtail - Papilio polyxenes
- Eastern Tiger Swallowtail - Papilio glaucus
- Polyphemus Moth - Antheraea polyphemus
- Five-spotted hawkmoth - Manduca quinquemaculata
- Banded Woollybear - Pyrrharctia isabella
- Auburn University Entomology and Plant Pathology | Whitemarked Tussock Moth
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