Top 15 Biggest Caterpillars In Maryland (Ranked Based on Size)

As we all know, Maryland is famous for fishing and horse farms. But do you know one more thing is there that is often noticed by people? There are many caterpillars in Maryland that you can find crawling on the bark, leaves, and trees. and here we are going to look at some of them based on their body length.

Here we go.

Top 15 Biggest Caterpillars In Maryland

15. Monkey Slug Caterpillar

Scientific name  Phobetron pithecium
Size 15-25 mm
Identification  Nine pairs of legs

One of the caterpillars in Maryland is the monkey slug caterpillar. This caterpillar has nine pairs of curly projections, or tubercles, each densely covered in hairs.

It has nine pairs of legs and prolegs, which are reduced to suction cups. Further, the arms or tubercles can fall off without harming the larva, aiding in defense.

Moreover, the larvae are 1.5–2.5 centimeters in length and are not a significant agricultural threat but are common in orchards. Also, they are solitary and not a significant agricultural threat.

14. Definite Tussock Moth Caterpillar

Definite Tussock Moth Caterpillar
Definite Tussock Moth Caterpillar | Credit: Ryan Hodnett (commons.wikimedia) CC BY-SA 4.0
Scientific name  Orgyia definita
Size Approx. 20 mm
Identification  Yellow head & spikes 

In 1865, the world learned about a new species of caterpillar with the help of the Alpheus spring Packard. This species is commonly found in the landscape of Maryland and different regions of the United States.

The caterpillar has a yellow head and a prothoracic plate. You can also identify this caterpillar by the white hairs covering its body and its pale yellow verrucae.

13. White Furcula Moth Caterpillar

Scientific name  Furcula borealis
Size 20-25 mm
Identification  Two horn-like projections from the shoulders

The White Furcula caterpillar has two tail-like projections and appears almost capable of stinging, possibly as a deterrent tool.

As it matures, it changes color, with young ones appearing black or purple with yellow bands and older ones appearing green with brown saddles.

Moreover, the head may appear flat when tucked in due to two horn-like projections from the shoulders. The front end is boxy and wider than the rear. Further, these caterpillars feed on aspen, cherry, poplar, and willow trees.

12. Woolly Bear Caterpillar

Woolly Bear Caterpillar
Woolly Bear Caterpillar | Credit: Brocken Inaglory (commons.wikimedia) CC BY-SA 4.0
Scientific name  Pyrrharctia isabella
Size 22-26 mm
Identification  Brown and black hair covering its whole body

Another caterpillar on the list of caterpillars in Maryland is Pyrrharctia isabella. You might know it by the name of a banded woolly bear or woolly worm.

This caterpillar turns into a moth, which is commonly seen flying in the United States and southern Canada.

If you are wondering how to identify this caterpillar, let us tell you that the larva has brown and black hair covering its whole body. The adult caterpillar has yellowish-orange thoraces, small heads, and bright reddish-orange forelegs.

After a long journey, this caterpillar turned into an Isabella tiger moth. It survives freezing by producing a cryoprotectant in its tissues.

Larval setae do not inject venom or cause irritation, injury, inflammation, or swelling. So stay conscious when you see this caterpillar around you.

11. Puss Moth Caterpillar

Scientific name  Megalopyge opercularis
Size 25 mm
Identification  Bright orange streak running longitudinally

If you see Megalopyge opercularis, then stay away from it. It is more dangerous than its cute look. This caterpillar converts into a moth in the Megalopygidae family.

You might hear some other name for it; it is also known by names such as southern flannel moth, puss caterpillar, asp, fire caterpillar, woolly slug, opossum bug, puss moth, tree asp, or asp caterpillar.

Furthermore, its inch-long larva is covered in hair-like setae, resembling a Persian cat. Its color ranges from grayish white to dark charcoal gray, with a bright orange streak running longitudinally.

Also, early-stage larvae have curly fur, while the middle instar has a disheveled appearance. The larva’s fur contains venomous spines that cause painful skin reactions.

10. Stinging Rose Caterpillar

Scientific name  Parasa indetermina
Size 23-30 mm
Identification  Smaller spiny bumps along each side

The stinging rose caterpillar is scientifically known as Parasa indetermina. Talking about its length, the caterpillar is slightly less than an inch long. But this little friend can cause a lot of pain if it stings.

If we confounded it to identify it, then we saw a caterpillar with seven pairs of spine-covered “horns” and smaller spiny bumps along each side. Also, the spines are hollow and filled with urticating fluid, which releases the fluid, causing a painful sting.

Furthermore, the caterpillar has white, black, orange, and red lines running along its back and sides. Female and male moths emerge in mid-summer, mate, and lay eggs for tiny caterpillars.

Moreover, the caterpillars feed, molt, and grow, hiding on the lower surface of their host plant leaves. In later summer, they spin a brown capsule-like cocoon, which they spend in the fall, winter, and spring.

9. Gold Moth Caterpillar

Gold Moth Caterpillar
Gold Moth Caterpillar | Credit: Katja Schulz (@flickr)
Scientific name  Basilodes pepita
Size Approx. 40 mm
Identification  Black patterns around its body like a tiger

 The gold moth caterpillar is observed to have distinctive color patterns. Mostly, it is seen in colors like orange, black, and white. Also, you can identify it through its distinctive pale and black rings around its body.

Other than that, it also had white spots on its body. Further, the head of the caterpillar is orange in color. The maximum length of the body is around 40 mm.

8. Large Tolype Moth Caterpillar

Scientific name  Tolype velleda
Size Approx. 45 mm
Identification  White fur on their thorax, legs

The Large Tolype Moth caterpillar is a large, white moth with a flap on its prolegs, which are fleshy legs that disappear after development.

Moreover, adults have a heap of white fur on their thorax, legs, and antennae, with a dark mohawk on the thorax and gray or taupe wings with thin white, wavy lines crossing them.

Further, females are paler than males, and the moth is medium to large. Furthermore, it feeds on the leaves and soft foliage of various trees and shrubs, with feeding most active in the summer.

7. Monarch Caterpillar

Monarch Caterpillar
Monarch Caterpillar
Scientific name  Danaus plexippus
Size 45-50 mm
Identification  White dots on the prolegs

The caterpillar has five stages, each lasting 3 to 5 days. The first instar is pale green or grayish-white, shiny, and almost translucent, with a large black head. Do you know the caterpillar feeds on milkweed in a circular motion, often leaving a characteristic arc-shaped hole in the leaf?

Further, the second instar develops a pattern of white, yellow, and black transverse bands, with a yellow triangle on the head and two sets of yellow bands around it.

Moreover, the third instar has more distinct bands, and two pairs of tentacles grow.

Furthermore, the fourth instar has white spots on the prolegs near its back, and the fifth instar has a more complex banding pattern and white dots on the prolegs.

As the caterpillar completes its growth, it is 4.5 to 5 cm long and 7 to 8 mm wide. The fourth- and fifth-instar stages showed signs of aggressive behavior with lower food availability.

6. Pipevine Swallowtail Caterpillar

Scientific name  Battus philenor
Size Approx. 50 mm
Identification  Bright orange spots on tubercles

Pipevine swallowtail caterpillars, resembling Alice in Wonderland, are purple with orange spots and long filamentous body protrusions. They are toxic to birds and animals, and they retain this trait when they become butterflies.

Larvae, ranging from dark brown to black, have bright orange spots on tubercles and are elongated into filaments.

They eat leaves from their host plants and move to new ones as food sources deplete. They identify vertical plants using filaments, feed, and wander for several weeks before finding an isolated spot to pupate.

5. Spiny Elm Caterpillar

Scientific name  Nymphalis antiopa
Size Approx. 50 mm
Identification  Creamy yellow band

The spiny elm caterpillar, Nymphalis antiopa, is found in northern Illinois and is known as the mourning cloak butterfly. It feeds on various trees, including elm and willow.

The immature form of the butterfly has a wingspan of two to three inches and is moderately sized.

It has dark brown wings with blue spots and a creamy yellow band. This butterfly overwinters as an adult, making it one of the first to appear in early spring. This year, several sightings were reported in early April.

4. Eastern Tiger Swallowtail Caterpillar

Scientific name  Papilio glaucus
Size Approx. 55 mm
Identification  The abdomen is spotted transversely in light blue

Another caterpillar on the list of caterpillars in Maryland is the Eastern Tiger Swallowtail Caterpillar. The caterpillar eats the leaves of a host plant and rests on a silk pad. Do you know? It has three brown instars and a large white saddle on the abdomen.

Furthermore, after molting to the fourth instar, it becomes green. Moreover, the swollen thorax has two black, yellow, and blue eyespots, smaller than the spicebush swallowtail caterpillar.

Other than that, you can identify the caterpillar by its yellow and black transverse stripe that is present between the first and second abdominal segments.

Further, the abdomen is spotted transversely in light blue. Another interesting fact about this caterpillar is that before pupating, the caterpillar turns dark brown and reaches 5.5 centimeters (2.2 in) in length.

3. Eastern Tent Caterpillar

Scientific name  Malacosoma americanum
Size Approx. 57 mm
Identification  A white stripe down the back

The next one is an eastern tent caterpillar, which is a species of moth producing one generation per year. It forms communal nests in tree branches and is often confused with the spongy moth and fall webworm.

It oviposits on trees in the Rosaceae plant family, particularly cherry and apple trees.

Do you know that caterpillars are known for their hair coloration and have areas of blue, white, black, and orange?

These are structural colors that are created by selective light filtering by microtubules on the cuticle.

2. Luna Moth Caterpillar

Scientific name  Actias luna
Size 70-90 mm
Identification  Green spines on the dorsal surface

This caterpillar, A. luna, has five instars before cocooning, each lasting 4–10 days. The larvae eat the leaves of walnut, hickory, sweetgum, and paper birch trees, with each instar being green and having green spines on the dorsal surface to protect them from predators. Do you know the final instar can grow up to 70 mm to 90 mm in length?

The caterpillar is tree-dwelling and stays on the same tree until it’s time to descend to the ground to make a cocoon. Females emerge from cocoons and fly to preferred tree species, emitting pheromones and waiting for males to find them.

Although some Saturniidae larvae are poisonous, A. luna’s spines, or setae, have no chemical component and are not poisonous. The caterpillar is tree-dwelling and lays eggs on preferred tree species.

1. Imperial Moth Caterpillar

Scientific name  Eacles imperialis
Size 76-139 mm
Identification  Larger black caterpillar with shorter bristles

Last but not least first place in the list of caterpillars in Maryland is an imperial moth caterpillar a small, orange caterpillar that hatches from an egg two weeks after hatching.

It grows from a small orange to a larger black caterpillar with shorter bristles and longer hairs. Further, the caterpillar can be green, red, cinnamon-colored, tan, burgundy, or charcoal gray.

Moreover, it molts once more and can reach 5.5 inches in size when ready to pupate. Also, instars eat by grabbing onto twigs and pulling leaves or pine needles, but their bristles and hairs don’t sting. The caterpillar then becomes a dark brown pupa with tapered segments and spines.


Here we come to an end. These are some of the species of caterpillars found in Maryland. The species of caterpillars in Maryland have a diverse range, and you can encounter these species in parks, farms, and any green area. If you want to know more about animals like caterpillars in Maryland, then keep looking for the same on HowItSee.


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