Types of Arizona Caterpillars (With Pictures) – Identification Guide
Caterpillars are a common sight in Arizona. Native Arizona caterpillars are typically large, worm-like creatures with cylindrical bodies. Common caterpillars in Arizona can be black and yellow with stripes, fat green larvae with dots or unusual markings, black spiky crawling insects, or black and orange furry caterpillars. Arizona also has types of stinging caterpillars, like the southern flannel moth caterpillar and the crowned slug moth caterpillar.
Species of Arizona caterpillars can be challenging to identify. All types of caterpillars go through growth stages called instars. During these four or five stages, the crawling larvae can change color, shape, and appearance. Also, caterpillars take on different characteristics depending on their food source and environment.
For example, the common Arizona caterpillar, the white-lined sphinx moth larva (Hyles lineata), is a slender, yellowish-green insect with black stripes. However, the long tube-like larva can be deep green or lime green with black and yellow dots and an orange or black tail in other areas.
This article is an identification guide to common caterpillars you are likely to find in Arizona’s landscape. Here you will find descriptions and pictures of Arizona’s furry, smooth-bodied, spiky, horned, stinging, and exotic caterpillars.
How to Identify Caterpillars in Arizona
To identify an Arizona caterpillar species, note the insect’s body shape, if it’s smooth, furry, or spiky, any particular markings, and if it has horns. Caterpillars are also identified by their six front legs and eight prolegs. Some caterpillars also have tufts of long pencil hairs or lashes.
Certain types of Arizona caterpillars can be identified by the host plants where they feed.
For example, the green and black striped monarch caterpillar (Danaus plexippus) feeds exclusively on milkweed plants. However, the Arizona white-lined sphinx caterpillar (Hyles lineata) and fuzzy banded woolly bear (Pyrrharctia isabella) are found on various deciduous shrubs and trees throughout the Grand Canyon State.
Types of Arizona Caterpillars (With Pictures)
Let’s look in detail at the identifying features of common Arizona caterpillars
White-Lined Sphinx Moth Caterpillar (Hyles lineata)
The white-lined sphinx caterpillar has many color variations, depending on its growth stage, and is common in Arizona
The white-lined sphinx caterpillar is a lime-green or yellow-green caterpillar with black stripes and markings. In Arizona, this caterpillar looks like a long, plump worm-like insect. The black and pale-green larva has a small brownish head and a fleshy horn-like tail. This Arizona caterpillar measures 2.7” (70 mm) long.
White-lined sphinx caterpillars are common in Arizona after the monsoon season. In years with heavy rainfall, masses of these yellowish-green striped larvae are seen in large groups. They can become a pest in gardens, swimming pools, hiking trails, and roadways.
Although the striped caterpillar has a black-tipped orange or brown sharp-looking horn, this fleshy protrusion isn’t a stinger. The white-lined sphinx caterpillar is harmless to humans.
After pupation, the long green caterpillar turns into an attractive brown and pink moth.
Arizona caterpillar identification
The white-lined sphinx moth caterpillar is easy to identify in the Arizona landscape. Its lime-green or yellow-green tube-like body has black stripes along its back and sides.
Two-Tailed Swallowtail Caterpillar (Papilio multicaudata)
The two-tailed swallowtail caterpillar turns from green to orangy-red before pupation
The two-tailed swallowtail caterpillar is the larva of Arizona’s state butterfly—the beautiful two-tailed swallowtail. The chubby caterpillar is identified by its humped back and conspicuous eyespots on its head. There are also bands of tiny dots traversing the caterpillar’s segments. The caterpillar has a slightly conical shape.
The two-tailed swallowtail caterpillar is green with pale white blotches, an enlarged head, and a yellow face when immature. During this stage, the green caterpillar looks somewhat like bird droppings. However, before pupation, the adult caterpillar is a reddish color with a black rim behind its enlarged head.
An identifying feature of this fat worm-like insect is its horn-like structure known as the osmeteria protruding from behind its head. This appears when the caterpillar feels threatened, and it also emits a foul stench.
Arizona caterpillar identification
The two-tailed swallowtail caterpillar is identified by its broad head and neck, small eyespots, and a black and white collar behind its head. The caterpillar is green but turning red-orange before pupation.
Cabbage Looper (Trichoplusia ni)
The green cabbage looper can cause a great damage to cabbage plants and is common in Arizona and other southern states
The cabbage looper is a harmless green caterpillar with a pale yellowish-green head and fine yellow bands separating its segments. The small green caterpillar has an identifiable crawling habit where it arches its back to form a looping motion. Sometimes the larva is entirely green; other times, it is paler with two broad white bands along its sides.
Before pupation, the green cabbage looper measures 1.2” to 1.5” (30 – 40 mm). These destructive green pests chew through cabbage leaves and can also bore into cabbage heads.
Apart from being common in Arizona, the cabbage looper is also a native caterpillar in Florida and other southern states.
Arizona caterpillar identification
The cabbage looper caterpillar’s most identifiable feature is its looping motion as it arches its back when crawling. In addition, the small pale green caterpillar usually has faint yellowish markings.
Cecropia Moth Caterpillar (Hyalophora cecropia)
The Cecropia moth caterpillar is a large green caterpillar with yellow and blue nodules
The cecropia moth larva is one of the most unusual caterpillars in Arizona. The identifying features of this bluish-green caterpillar are orange, yellow, and blue ball-like spiked tubercles sitting on ridged segments. There are also bluish tubercles on its eight prolegs. The caterpillar’s head section is wider than its tail end.
The cecropia moth caterpillar reaches enormous lengths of 4” to 4.5” (100 to 110 mm). During its instars, this strange-looking Arizona caterpillar changes from a spiky black caterpillar to yellowish-green, then bluish green covered in colorful tubercles.
Arizona caterpillar identification
The cecropia moth caterpillar is identified by its yellow, orange, blue, and sometimes red spiked projections on its bluish, sea-green body.
Banded Woolly Bear Caterpillar (Pyrrharctia isabella)
The banded woolly bear caterpillar is a furry caterpillar with black and orange or brown hairs
The banded woolly bear larva is an easily recognizable Arizona caterpillar due to its black fuzzy body with a brown-orange band around its middle. This black and orange furry caterpillar is not a stinging caterpillar, and its spiny covering doesn’t cause skin irritation. However, its sharp, spiny hairs can cause dermatitis in some people.
The black and brown hairy caterpillar is medium-sized, measuring around 2” (50 mm) long just before pupation. Apart from its bronze-colored band, an identifying feature of the woolly bear is how it rolls into a ball when threatened.
Arizona caterpillar identification
The banded woolly bear caterpillar is easily recognizable due to its furry black and brown body.
Common Buckeye Caterpillar (Junonia coenia)
The common buckeye caterpillar has several color variations
The common buckeye caterpillar is a black, spiny caterpillar with orange markings, and an orange head. However, the species has several color variations. Some spiky black caterpillars have white stripes and brown markings, and others are without stripes but are covered in tiny white speckles.
The spiky black caterpillars measure 1.5” (40 mm) long with spiny, fleshy tufts along their cylindrical bodies. You can find these long slug-like spiny larvae feeding on plantain, foxglove, and petunias.
Arizona caterpillar identification
The common buckeye caterpillar is easy to spot due to its numerous dark-blue or black branched spines, white or lime-green stripes, and orangey-brown spots.
Monarch Caterpillar (Danaus plexippus)
The monarch caterpillar has yellow, white, and black stripes
The monarch butterfly larva is a striking striped caterpillar with black, white, and yellow bands around its abdomen. The large black and white caterpillar also has fleshy horns at either end of its stripy abdomen. The harmless monarch caterpillar in Arizona grows up to 1.7” (45 mm) long.
Apart from its stripy appearance, this Arizona caterpillar has two pairs of black fleshy horns—two long ones at one end and two shorter ones at the other end.
Due to its diet, the monarch caterpillar is poisonous to birds and predators. The large, plump cylindrical insect feeds on milkweed plants which create toxins in the caterpillar’s body—a deterrent making it taste nasty to other insects and birds.
Arizona caterpillar identification
The monarch butterfly is easy to identify due to its characteristic black, yellow, and white stripes traversing its abdominal segments.
Viceroy Caterpillar (Limenitis archippus)
The viceroy caterpillar has brown, orange and white body with spiky horns at its head
The viceroy butterfly larva is a strange-looking brown caterpillar with mottled white patterns. This caterpillar’s abdomen has distinctive bumps, spiked protrusions, and dotted markings. In some instars, the viceroy caterpillar looks like bird droppings. The orange-brown and white spiny humped ugly viceroy caterpillar measures 0.6” (15 mm) long.
Viceroy caterpillars are often found on willow and cottonwood trees.
Arizona caterpillar identification
The viceroy caterpillar is identified as an orange-brown bumpy caterpillar that looks like bird poop.
Variegated Fritillary Caterpillar (Euptoieta Claudia)
The large variegated fritillary caterpillar is identified by its orange-red spiked body with black and white lines
The larva of the variegated fritillary butterfly is an eye-catching orange or red Arizona caterpillar with numerous branched black spikes. The orange caterpillar also has identifiable rows of oval, bright white dots, brown-black legs and prolegs, and a pair of clubbed spines on its thorax.
The large orange and black variegated fritillary caterpillar is a tube-like insect measuring 3.5” (90 mm) long.
Arizona caterpillar identification
The variegated fritillary caterpillar is an orange caterpillar with longitudinal white and black stripes along its tubular body.
Tobacco Hornworm (Manduca sexta)
The tobacco hornworm caterpillar is a large green caterpillar with white diagonal stripes
Also called the goliath worm, the tobacco hornworm caterpillar is a huge green insect with white diagonal stripes and black dots along its sides. This type of horned caterpillar also has a distinctive curled head and a rosy-pink curved horn-like tail. Also called the Carolina sphinx moth, the large caterpillar grows 2.7” (70 mm) in length.
The tomato hornworm (Manduca quinquemaculata) looks like the related tobacco hornworm caterpillar. The difference between the tobacco hornworm and the tomato hornworm is their markings and size. The tomato hornworm is 4” (100 mm) long and has V-shaped markings, not diagonal ones.
The tomato hornworm caterpillar has white V-shaped markings
Arizona caterpillar identification
The enormous tobacco hornworm is a pale green, cylindrical caterpillar with pale white and black lateral markings.
Giant Swallowtail Caterpillar (Papilio cresphontes)
The giant swallowtail caterpillar looks like bird droppings. The pictures shows its red osmeteria, a structure that appears when the caterpillar feels threatened
The giant swallowtail is the larva of the largest butterfly in Arizona and North America. The ugly brown caterpillar has mottled white, black, and brown patterns, making the larva look like bird droppings. This camouflage defense mechanism makes the caterpillar hard to spot on tree and shrub branches.
The brown humpbacked giant swallowtail caterpillar measures 2” (50 mm) long.
Arizona caterpillar identification
Also called orange puppy or orange dog, the brown caterpillar with its enlarged head is identified by its white and dark brown blotches.
Polyphemus Moth Caterpillar (Antheraea polyphemus)
the plump green polyphemus moth caterpillar has red dots with fine spikes along its body
The polyphemus moth caterpillar is a bright green silkworm with delicate spines emerging from red dots along its cigar-shaped body. This fat green, stumpy caterpillar is a small green spiky caterpillar when immature. It becomes engorged and plump as it feeds on birch, willow, hickory, and elm leaves.
The polyphemus caterpillar grows 3” to 4” (75 – 100 mm) long and is easily recognizable due to its neon-red spots.
Arizona caterpillar identification
The polyphemus silk moth caterpillar is easy to spot due to the bands or red bumps around each segment of its bright green body.
Red Admiral Butterfly Caterpillar (Vanessa atalanta)
The red admiral caterpillar has black spiky body with tiny white dots
The red admiral caterpillar is a distinctive black caterpillar covered with fleshy black branched spines and tiny white dots. The spiky black caterpillar is slender during most instars. Before pupation, the caterpillar grows 1” (25 mm) long and becomes dark brown with thin black jagged spines.
Arizona caterpillar identification
The identifying feature of the red admiral caterpillar is its shiny black body covered in bands of spiny spikes.
Silver-Spotted Skipper Caterpillar (Epargyreus clarus)
The silver-spotted skipper caterpillar has yellow body with fine green stripes and brown-reddish head
The silver-spotted skipper caterpillar is a yellow caterpillar with thin green bands around its segments and a conspicuous ball-like reddish brown head. The striped, yellow caterpillar has identifying characteristics like bright orange eye spots, bright red throat, and red feet. The yellowish-green caterpillar measures 2” (50 mm) long.
Arizona caterpillar identification
The silver-spotted skipper caterpillar is identified by its striped plump yellow body and globular reddish-brown head with two large orange spots.
Spotted Tussock Moth Caterpillar (Lophocampa maculata)
The yellow-spotted tussock caterpillar has a distinctive look with its yellow and black hairs
The easily identifiable spotted tussock moth caterpillar is a hairy yellow and black caterpillar with prominent tufts of long pencil hairs and a row of black dots on its yellow band. The small fuzzy, yellow-banded caterpillar also has the common name yellow woolly bear. This yellow and black insect grows 1.1” (30 m) long.
You will find the black-spotted yellow tussock caterpillar feeding on poplar, willow, birch, oak, and maple trees.
Arizona caterpillar identification
The spotted tussock moth caterpillar is a black and yellow hairy caterpillar with numerous long white lashes sticking out from either end.
Crowned Slug Caterpillar (Isa textula)
The unusual-looking crowned slug caterpillar has stinging spines along its sides
The crowned slug caterpillar is a strange-looking Arizona caterpillar with a flattened oval body covered in stinging spines. Apart from the venomous yellow spines, the green stinging caterpillar has red or yellowish margins and two raised yellow lines on its back.
The tiny oval caterpillar looks like a leaf that grows 0.6” (15 mm) long. It’s best to stay clear of this spine-covered green caterpillar because it can give you a nasty sting.
Arizona caterpillar identification
The crowned slug caterpillar is easy to recognize due to the yellow spiny protrusions around its green oval body.
Western Tent Caterpillar (Malacosoma californicum)
The hairy Western tent caterpillar has a long black and orange body
The western tent caterpillar is a slender worm-like furry larva covered in orange or dark yellow tufts of fine setae (hairs). The orange and black caterpillar gets its name from the tent-like web structures where hundreds of the leaf-destroying bugs live. The furry caterpillars can grow up to 2.5” (50 mm) long.
Arizona caterpillar identification
The western tent caterpillar is identified by a striking orange stripe and wispy orange hairs covering its tube-like black body.
Black Swallowtail (Papilio polyxenes)
The black swallowtail caterpillar is identified by its black stripes and yellow markings on its green body
The black swallowtail larva tail is a large, engorged bright green caterpillar with bands of yellow and black markings. The striped, green larva has identifiable black bands with yellow spots around each segment. Just before pupation, this stripy green caterpillar grows around 1.5” (40 mm). However, the immature black swallowtail caterpillars are black and white.
The black swallowtail caterpillar in Arizona is a poisonous type of crawling insect. Although it’s harmless to humans, the larva develops toxins that make it toxic to birds and predators.
Arizona caterpillar identification
The black swallowtail caterpillar is a large green caterpillar, identified by its black and yellow stripes around its body.
Southern Flannel Moth Caterpillar (Megalopyge opercularis)
The furry Southern flannel caterpillar has light brown hairs and is commonly found in Arizona
The southern flannel moth larva is a type of hairy stinging caterpillar found throughout Arizona. The brown venomous caterpillar has a deceptive soft appearance. Despite being covered in luxuriant hairs, the fluffy hairs hide the stinging spines on this tiny furry caterpillar. This stinging caterpillar grows between 1” and 1.5” (25 – 38 mm).
The southern flannel moth caterpillar adapts well to hot, dry environments—which is why the caterpillar is commonly found in Texas and Arizona. Other names for the unusual stinging insect are Fire caterpillar, puss moth, tree asp, and woolly slug.
Arizona caterpillar identification
The southern flannel moth caterpillar has a distinctive appearance with its curly golden brown disheveled hairs covering a teardrop-shaped body.
Yellownecked Caterpillar (Datana ministra)
The yellownecked caterpillar has black and yellow bands along its hairy body
The yellownecked moth larva is a black and yellow striped caterpillar with an orange throat and bulbous black head. A feature of the stripy Arizona caterpillar is wispy spines giving it a fuzzy appearance. This yellow and black hairy caterpillar has a cylindrical body that measures 1” (50 mm) long.
Arizona caterpillar identification
The identifying characteristics of a yellownecked caterpillar are the yellow stripes running from head to tail on a black hairy body.
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