North American Caterpillar Identification

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 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 Woolly Bear (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 redhead 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!

1. Banded Woolly Bear

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 members of the Arctiidae family, which includes tiger moths and some of our most beautiful Lepidoptera. Woolly bears become the Isabella tiger moth.

How to Identify a Woolybear

Woolly bears 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, though their bristles are actually quite hard.

This familiar orange and black caterpillar can often be found hustling across rural roads in late summer. Woolly bears 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!

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

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 shiny brown 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 by green, and its horn is blue. The tobacco hornworm, on the other hand, has six white stripes bordered by black, and its horn is red. Below are photos of both types of hornworm.

How to Get Rid of Hornworms

Both types of hornworms 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.

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 single big 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.

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