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 yourself just found a caterpillar, and you're looking for a little help with identification.If so, you're are in the right place! I have been helping people with caterpillar identification for many years, 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.
Is your caterpillar rare? What does it turn into? Is your caterpillar able to sting you? (Yes -- there are stinging caterpillars, and here's a good guide with lots of pictures).
This article is intended to help you identify that caterpillar you found crawling across your kitchen floor, or driveway, or up the side of your house. Green caterpillars, furry caterpillars, caterpillars on tomato plants, even caterpillars on houseplants -- I hope you find your caterpillar here!
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Caterpillar Identification: White-Marked Tussock Moth
Caterpillar Identification: White Marked Tussock Moth
This cool-looking caterpillar can be vary common 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 s;pines that can cause a rash in some people, so handle with care!
The moth that these caterpillars 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 lays a foamy mass of eggs right on the cocoon!
Caterpillar Identification: Woolly Bear
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," scientific name 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 the caterpillar's body. Handling a cocoon can give you little slivers, a little like handling fiberglass insulation.
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Tomato Horn Worm
Caterpillar Identification: Tomato Hornworm
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 tomato plant down to the stem, and there are big holes being gnawed in the tomatoes, then these big green caterpillars 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 these cateprillars 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 adult 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.
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Caterpillar Identification: Polyphemus Giant Silk Moth
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, and 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 food 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 give them their name, "Polyphemus," which refers to the one-eyed cyclops in <i>The Odyssey.
Caterpillar Identification: Tiger Swallowtail
This pretty green caterpillar 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 it can stick out from behind its head if it feels threatened. The osmeterium looks like a small snake's tongue, which might scare off predators, and it smells bad, too. This defensive organ is unique to the swallowtails.
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Caterpillar Identification: Black Swallowtail
I have had these pretty green and black caterpillars on my carrots every year sine I can remember. Like the above species, this swallowtail caterpillar has an "osmeterium," a defensive scent organ that also resembles a snake's tongue. Sometimes known as a "parsley worm," black swallowtail caterpillars 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.
Caterpillar Identification: Monarch
One of the best-known butterflies in North America, the monarch is famous for its astounding migrations across half a continent to winter in piney mountains in Mexico. That feat is enough to make the monarch impressive, but there are more. The monarch caterpillar eats only milkweed species, 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 the caterpillar 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 called mimicry, and there are many species that look like the monarch for this reason.
Caterpillar Identification: Tersa Sphinx
This cool-looking caterpillar belongs to the sphinx moth group, which includes the tomato horn worm and many other big caterpillars. The false eyes on the head may scare away predators, and the caterpillar acts like a small snake when threatened. The moths are sleek and streamlined, and look a little a 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.
Caterpillar Identification: Imperial Moth
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 caterpillar 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.
Caterpillar Identification: Noctua Pronuba
This species is a kind of "cutworm," a group that feed on low plants, often eating through the stem near the ground,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 is quite variable -- the forewings, or "primaries," may be dark brown or light tan. The underwings are bright yellow, giving it it's name in Britain: "the large yellow underwing."
Caterpillar Identification: Rustic Sphinx
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
Caterpillar Identification: American Dagger Moth
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 cateprillars have "boring" moths, but the pattern is often repeated across the Insect world.
Caterpillar Identification: Saddleback Caterpillar
This caterpillar 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 the Limacodidae family, which also includes other stinging caterpillars of various interesting designs.
These caterpillars turn into a pretty brown moth with variable green and orange patches on the upper wings.
Caterpillar Identification: The Asp
This is a stinging caterpillar 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 caterpillars are more common in the south, where their appearance -- and their stings -- are often well-known.
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Caterpillar Identification: The Banded Sphinx
This gorgeous caterpillar 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, the banded sphinx. This caterpillar is big and bright enough that people often find it on branches of the preferred food plant, water primrose.
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