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Caterpillar Identification Guide: Find Your Caterpillar With Photos and Descriptions

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The beautiful black swallowtail caterpillar is often found on parsley or dill.

The beautiful black swallowtail caterpillar is often found on parsley or dill.

Identify Your Caterpillar With This Easy, Accurate Guide

If you have found a caterpillar and you're wondering what it will turn into or if it will damage your garden, then this easy, photo-rich caterpillar identification guide will help.

This guide will answer many of your questions: Does this caterpillar sting? Is it rare? Is it a serious garden or forest pest? Whether you're a young scientist looking for information for a project, a gardener with big green caterpillars all over your tomatoes, or you simply want to know what that thing crawling across your patio might be, there's something here for you.

The cecropia moth caterpillar, one of the largest and most impressive species in North America, is completely harmless and does not sting.

The cecropia moth caterpillar, one of the largest and most impressive species in North America, is completely harmless and does not sting.

How to Use This Guide

For every caterpillar listed, this guide will tell you the following essential information:

  • Does it sting?
  • What does it eat?
  • Will it seriously damage plants or trees?
  • Is it rare?
  • What does it turn into?
  • Can you raise it to an adult?

If you still have questions about identifying the caterpillar you found, below you will find good internet sources that are species-specific and can give you more detail.

Use This Chart to Quickly Find Your Caterpillar in This Guide

* Bear in mind that immature or "baby" caterpillars can be less than one inch, even though the fully grown caterpillar may be much larger.

ColorSize*Fur or Spines# In This Guide

Green

Less than one inch

Yes

34

Green

One inch or more

Yes

12, 13, 15, 18, 25

Green

One inch or more

No

14, 20, 21, 26, 27, 30, 35

Red/Yellow/Orange

Less than one inch

Yes

22, 32, 33,

Red/Yellow/Orange

One inch or more

Yes

3, 4, 6, 7, 8, 10, 11, 16, 17, 18, 23, 24, 28, 29

Red/Yellow/Orange

One inch or more

No

1, 2, 36

Black or brown

One inch or more

Yes

5, 12, 19,

Black or brown

One inch or more

No

9, 21, 26, 27, 30, 31

First, a Quick Science Lesson: What Are Caterpillars?

Caterpillars are the larval stage of the class of insects called Lepidoptera, commonly known as butterflies and moths. They spend their days eating and storing energy to become adult butterflies or moths. Caterpillars are well-adapted to their natural surroundings.

Most of them are camouflaged, so we usually don't see them even though they're all around us. They are so perfectly disguised (or have such secretive habits) that we walk right by them without ever knowing they're there. But they are!

Butterflies and moths go through "complete metamorphosis"—that is, they have four distinct stages: egg, larva, pupa, and adult. The caterpillar is the larval stage; all a caterpillar does is eat and store energy for the adult stage. They are eating machines whose only goal is to store fat for adulthood.

Caterpillars are cool! They are often camouflaged, but many have bright colors and patterns that may serve to warn or scare away predators, like birds. Most caterpillars are totally defenseless, but stinging spines protect a few species.

Now that you know what a caterpillar is let's find out what kind of caterpillar you have!

Numerical Order of Caterpillars in This Guide

#1-10#11-20#21-30#31-38

1. Danaus plexippus: The Monarch

11. Halysidota harrisii: The Sycamore Tussock

21. Abbott's Sphinx: Sphecodina abbottii

31. Papilio cresphontes: The Giant Swallowtail

2. Papilio polyxenes: the Black Swallowtail

12. The Imperial Moth: Eacles imperialis

22. Euchaetes egle: The Milkweed Tussock Moth

32. Orgyia leucostigma: The White-Marked Tussock Moth

3. Vanessa cardui: The Painted Lady

13. Hyalophora cecropia: The Cecropia Giant Silk Moth

23. Lymantria dispar: The Gyspy Moth

33. Megalopygidae opercularis: The Puss Moth, Asp, or Elvis Caterpillar

4. Vanessa virginiensis: The American Painted Lady

14. Antheraea polyphemus: The Polyphemus Giant Silk Moth

24. Malacosoma disstria: The Forest Tent Caterpillar

34. Acharia stimulea: The Saddleback Caterpillar

5. Vanessa atalanta: The Red Admiral

15. Callosamia promethea: The Promethea Giant Silk Moth

25. Citheronia regalis: The Regal Moth

35. Papilio troilus: The Spicebush Swallowtail

6. Acronicta oblinita: The Smeared Dagger Moth

16. Pyrrharctia isabella: The Banded Woolly Bear

26. Eumorpha pandorus: The Pandorus Sphinx Moth

36. Protographium marcellus: The Zebra Swallowtail

7. Euptoieta claudia: The Variegated Fritillary

17. Spilosoma virginica: The Yellow Woolly Bear

27. Ceratomia catalpae: The Catalpa Sphinx Moth

37. Eumorpha fasciatus: The Banded Sphinx Moth

8. Agraulis vanillae: The Gulf Fritillary

18. Automeris io: The Io Moth

28. Nymphalis antiopa: The Mourning Cloak Butterfly

38. Dryocampa rubicunda: The Rosy Maple Moth

9. Cutworms and Related Caterpillars: Genus Xestia and Others

19. Genus Hemileuca: Buck Moths

29. Acronicta americana: The American Dagger Moth

10. Silver-Spotted Tiger Moth: Lophocampa argentata

20. Manduca Species: Tomato and Tobacco Hornworms

30. Pterorous glaucus: The Tiger Swallowtail

The Monarch caterpillar feeds exclusively on milkweeds

The Monarch caterpillar feeds exclusively on milkweeds

1. Danaus plexippus: The Monarch

This cool caterpillar is always found on some species of milkweed (Asclepias species). They aren't too hard to spot, with their bright stripes of black, white, and yellow. The milkweed that monarchs feed on is protected by poisonous sap, which in turn makes the monarch caterpillar poisonous to any potential predators. Not a bad form of protection! They are brightly colored and turn into one of the most beautiful and popular of all butterflies: the monarch.

Monarch Butterfly

Monarch Butterfly

Quick Facts

  • Does it sting? No.
  • What does it eat? Milkweeds.
  • Will it seriously damage plants or trees? No—milkweed is a common roadside plant.
  • Is it rare? No, although pesticide run-off is threatening its foodplant!
  • What does it turn into? The beautiful monarch butterfly.
  • Can you raise it to an adult? Yes, it does well in captivity.

Monarch Caterpillar Changes to a Chrysalis

Want to Help Keep Monarch Butterflies From Becoming Endangered?

You can easily make a big difference simply by planting a few milkweed plants in your yard. Monarchs will visit the flowers and lay eggs on the leaves. Milkweed is the only kind of plant Monarch caterpillars eat, and without it, they'll die.

Many pesticides used by modern agriculture poison and kill milkweed plants, so you can help Monarchs by planting milkweeds yourself. The seeds are free. This article shows you how to get started!

The black swallowtail caterpillar eats carrots, parsley, and fennel

The black swallowtail caterpillar eats carrots, parsley, and fennel

2. Papilio polyxenes: The Black Swallowtail

This caterpillar looks a lot like the monarch caterpillar (above), which may not be an accident. The monarch is most likely "protected" by the bitter sap of the milkweed plant that it eats because some of the toxic compounds in the sap become incorporated into the insect's tissues.

The black swallowtail caterpillar eats the leaves of carrots and other Umbelliferae species, which gives them little protection. But sometimes, just looking like you're poisonous can be protection enough—that's the basis of one major form of mimicry. It's thought that the black swallowtail caterpillar mimics the monarch caterpillar so birds and other predators might leave it alone, putting a mistaken identity to good use!

These caterpillars can be kept in a safe, unbreakable habitat designed for raising caterpillars. Make sure you give them plenty of the host plant—for this species, carrot or dill—you found them on.

This attractive caterpillar turns into a beautiful, big butterfly known as the black swallowtail.

Black Swallowtail Butterfly

Black Swallowtail Butterfly

Quick Facts

  • Does it sting? No.
  • What does it eat? Parsley, carrots, and dill.
  • Will it seriously damage plants or trees? Sometimes they can eat a lot of carrot greens.
  • Is it rare? No, but it isn't always common in all areas.
  • What does it turn into? The gorgeous black swallowtail butterfly.
  • Can you raise it to an adult? Yes, if you give it an upright stick to pupate on.
The painted lady caterpillar is often included in butterfly-raising kits.

The painted lady caterpillar is often included in butterfly-raising kits.

3. Vanessa cardui: The Painted Lady

The painted lady butterfly is likely the most widespread butterfly species in the world—it occurs nearly everywhere and has many subspecies and forms. The caterpillar is spiny but harmless and, in fact, is the species most often included in butterfly rearing kits. In these kits, you receive a coupon to send in for eggs or newly hatched caterpillars, which feed on a kind of paste included in the kit. In nature, of course, the caterpillars feed on leaves—usually asters, but also many other plants.

Painted lady butterflies are known to migrate in large numbers, spreading far beyond their usual range.

caterpillar-identification-2

Quick Facts

  • Does it sting? No.
  • What does it eat? Asters and other leaves.
  • Will it seriously damage plants or trees? Not usually.
  • Is it rare? No, but it isn't always common in all areas.
  • What does it turn into? The pretty Painted Lady butterfly.
  • Can you raise it to an adult? Yes, if you give it an upright stick to pupate on.
The American Painted Lady caterpillar

The American Painted Lady caterpillar

4. Vanessa virginiensis: The American Painted Lady

Also known simply as the American Lady, this bright orange butterfly is very similar to the more common painted lady, Vanessa cardui, which is the species most often included in butterfly-rearing kits. The American Lady is brighter orange, a bit smaller, and flies earlier in the year. Other "lady" butterflies exist across the United States as well as worldwide.

This caterpillar feeds on asters, including everlasting. It has spines but is completely harmless to humans. These caterpillars are generally easy to raise. They make a chrysalis, as virtually all butterfly species do, but they do not spin a cocoon.

caterpillar-identification-2

Quick Facts

  • Does it sting? No.
  • What does it eat? Asters.
  • Will it seriously damage plants or trees? Not usually.
  • Is it rare? No, but it isn't always common in all areas.
  • What does it turn into? The pretty American Lady butterfly.
  • Can you raise it to an adult? Yes, if you give it an upright stick to pupate on.
Red Admiral caterpillars eat stinging nettle

Red Admiral caterpillars eat stinging nettle

5. Vanessa atalanta: The Red Admiral

This very common species is one of the most often-seen butterflies in urban areas. It has a quick and nervous flight, but it lands frequently; males will often patrol areas around porches and yards in the late afternoon, returning to the same perch after each tour of the territory. This butterfly is also well-known for its habit of landing on people it evidently regards as a suitable perch.

The caterpillar of this charming butterfly feed in groups on nettles. You will sometimes find their nests in the summer, with many individuals and a whole lot of poop as well. They likely gain some protection by making this stinging plant their home.

Red admiral caterpillars are dark, with jagged yellow markings on the side. Their black spines cover most of the body, making it even more difficult for predators to get anything more than a mouthful of prickles should they decide to attack.

caterpillar-identification-2

Quick Facts

  • Does it sting? No, although the spines are sharp.
  • What does it eat? Nettles.
  • Will it seriously damage plants or trees? Not usually.
  • Is it rare? No—this species is among the most common North American butterflies.
  • What does it turn into? A pretty red and black butterfly.
  • Can you raise it to an adult? Yes, if you give it plenty of fresh leaves.
The smeared dagger moth caterpillar

The smeared dagger moth caterpillar

6. Acronicta oblinita: The Smeared Dagger Moth

The adult moth of this species, like all dagger moths, is gray with black spots and chevrons, including a vaguely dagger-shaped mark at the lower corner of the upper wing; this is where the group gets its common name.

The spiny caterpillar of the smeared dagger moth feeds on many plants and is among the more common moth caterpillars in the eastern US. It has a characteristic jagged yellow line down its side which makes it look quite similar to another spiny caterpillar in this guide, the red admiral butterfly.

This species is common enough that it can sometimes be considered a pest in the fruit industry due to its ability to strip small trees of leaves.

This is a typical dagger moth, similar to the smeared dagger moth.

This is a typical dagger moth, similar to the smeared dagger moth.

Quick Facts

  • Does it sting? No, although the spines are sharp.
  • What does it eat? Many plants and trees.
  • Will it seriously damage plants or trees? Yes, occasionally.
  • Is it rare? No.
  • What does it turn into? A drab gray moth.
  • Can you raise it to an adult? Yes, if you give it plenty of fresh leaves.
The caterpillar of the variegated fritillary

The caterpillar of the variegated fritillary

7. Euptoieta claudia: The Variegated Fritillary

The variegated fritillary is not a true fritillary, despite superficially resembling members of that group. This butterfly is something like a paler version of the gulf fritillary, with a "smeared" look to the underside and no metallic silver markings. While it is related to the true fritillaries, the variegated fritillary exhibits some distinct differences:

  • Variegated fritillaries have two or three broods per year vs. one per year in Speyeria.
  • They are nomadic vs. sedentary.
  • They use a wide range of host plants vs. just violets.
  • Variegated fritillaries also have taxonomic links to the heliconians.
  • Their flight is low and swift rather than high and gliding.

Variegated Fritillary Caterpillar Feeding

Another characteristic of this species is the fact that they are very hard to approach; accordingly, its genus name was taken from the Greek word euptoietos, meaning "easily scared."

This beautiful spiny caterpillar becomes an even more beautiful pupa marked with cream, orange, and metallic silver spines. The caterpillar's food plants include moonseed, flax, passionflower, plantain, pansy, and violets.

caterpillar-identification-2

Quick Facts

  • Does it sting? No, although the spines are sharp.
  • What does it eat? Many plants, including moonseed, flax, passionflower, plantain, pansy, and violets.
  • Will it seriously damage plants or trees? Not usually.
  • Is it rare? No, although it is more common in the South.
  • What does it turn into? A pretty orange and black butterfly.
  • Can you raise it to an adult? Yes, if you give it plenty of fresh leaves.
The caterpillar of the gulf fritillary

The caterpillar of the gulf fritillary

8. Agraulis vanillae: The Gulf Fritillary

The gulf fritillary is a simply gorgeous butterfly, one of the most striking insects in North America. It has the orange-and-black upperside of most fritillary species, but underneath, it is shaded with crimson, rich coffee-brown, and bright, metallic silver spots.

Interestingly, it is not a true fritillary; it's a member of a tropical group of butterflies sometimes called longwings or heliconiids. No other members of this group resemble the gulf fritillary, and the group is well-known for its mimicry of other species, so it's likely that the gulf fritillary is "copying" the colors of the true fritillaries in order to gain some protection from predators.

Of course, it could also be the other way around, an idea supported by the fact that heliconiid caterpillars feed on vines—in this case, Passiflora vines—that are known to have toxic sap.

Whatever the case, the spiny caterpillar of the gulf fritillary, is sometimes found on passion flower vines, especially in Florida and Texas. It is a southern species but is sometimes spotted as far north as the Great Lakes.

Agraulis vanillae, mating pair

Agraulis vanillae, mating pair

Quick Facts

  • Does it sting? No, although the spines are sharp.
  • What does it eat? Passion flower vines.
  • Will it seriously damage plants or trees? Yes, it can occasionally remove the leaves from the host plant.
  • Is it rare? Not in the South, but in the North, it is seldom seen.
  • What does it turn into? A gorgeous butterfly.
  • Can you raise it to an adult? Yes, if you give it plenty of fresh leaves.
Cutworms live in the soil and eat almost any plant.

Cutworms live in the soil and eat almost any plant.

Cutworms are the caterpillars of a group of moths in the family Noctuidae, a very large group encompassing many species. Cutworm species are often in the genus Xestia but may be in many other genera. Either way, the caterpillars and the moths all look very much alike.

Cutworms eat many plants and get their name from their habit of eating through the stem close to the ground, "cutting down" the entire plant. They generally feed at night and spend the day curled up just below the surface, where you will find them when digging in your garden.

Cutworm moths are brown or gray, fairly large, and not very noticeable. If you see brown moths milling around your porch light on a warm summer night, the chances are good that they belong to this group.

Xestia baja, a typical cutworm moth.

Xestia baja, a typical cutworm moth.

Quick Facts

  • Does it sting? No, these caterpillars are harmless to people.
  • What does it eat? Many plants, including garden plants.
  • Will it seriously damage plants or trees? Not usually, although they can eat a lot of leaves and potentially damage your garden.
  • Is it rare? No.
  • What does it turn into? A medium-sized brown moth.
  • Can you raise it to an adult? Yes, these are easy to raise.
The silver-spotted tiger moth caterpillar has irritating spines.

The silver-spotted tiger moth caterpillar has irritating spines.

10. Silver-Spotted Tiger Moth: Lophocampa argentata

The silver-spotted tiger moth is one of a large group of insects known as tiger moths that occur throughout North America and Europe. A few adult moths in this group are strikingly beautiful, but all of them are interesting insects with bold patterns and cool natural histories.

The silver-spotted tiger moth is notable mainly because its fur is likely to trigger allergic reactions in those with sensitivities. Contact with the caterpillar's short, stiff hairs can induce an itchy rash; in some people, the reaction can be bad enough to require medical treatment. However, it's important to note that this insect is not venomous. Some caterpillars possess venomous spines, but the silver-spotted tiger moth is not one of them.

Adult Silver-Spotted Tiger Moth

Adult Silver-Spotted Tiger Moth

Quick Facts

  • Does it sting? No, but its fur can cause allergic reactions.
  • What does it eat? Douglas fir and other western trees.
  • Will it seriously damage plants or trees? Not usually.
  • Is it rare? No, but it isn't always common in all areas.
  • What does it turn into? A pretty pale brown and silver moth.
  • Can you raise it to an adult? Yes, if you give it enough fresh leaves.
Sycamore Tussock Moth Caterpillar

Sycamore Tussock Moth Caterpillar

11. Halysidota harrisii: The Sycamore Tussock

This species is closely related to the silver-spotted tiger moth (above). In fact, the common name "tussock moth" should properly be reserved for a different group, moths in the family Lymantriidae, unrelated to the tiger moths. But common names are a reality, and so the confusion will persist.

H. harrisii is quite common in some parts of the United States. You'll most likely find it wandering around, looking for a safe place to make a cocoon. The moth is a pretty brown-and-cream color and is part of the genus Halysidota, which includes many similar species found all over the US.

Sycamore Tussock Moth

Sycamore Tussock Moth

Quick Facts

  • Does it sting? No, although the fur may be irritating to sensitive skin.
  • What does it eat? Sycamores and related plants.
  • Will it seriously damage plants or trees? No, it seldom occurs in enough numbers to do damage.
  • Is it rare? No.
  • What does it turn into? A cool, pale-brown tiger moth.
  • Can you raise it to an adult? Yes—it will spin a cocoon in the container.

Sycamore Tussock Caterpillar Crawling

12. The Imperial Moth: Eacles imperialis

This huge caterpillar is often found in late summer when it leaves the comfort of the tree it has been living in and wanders off to find a place to pupate. This species pupates underground and does not spin a cocoon, so it has to find the right place to spend the winter and turn into a moth.

Often these caterpillars are found on the ground right before they pupate; at this time, their usual green color is dark, almost purple, and they are beginning to contract into the pupal form.

This big caterpillar turns into a very big moth, one of the largest in North America. The imperial moth is perfectly camouflaged to blend into the yellowed leaves of poplars and other trees, so despite its size, it can be very easy to miss. You are much more likely to see this magnificent species as a caterpillar than the adult moth.