Bug Encyclopedia
Search and identify bugs & insects — beetles, butterflies, moths, ants, bees, spiders and more — with size, habitat, danger, behavior, and how to tell them apart.

Monarch Caterpillar
A boldly banded caterpillar in white, yellow, and black stripes, unmistakable as it munches its way through milkweed leaves before transforming into North America's most famous migratory butterfly.
caterpillar-larva
Caterpillar
The soft-bodied, segmented larval stage of butterflies and moths, recognized by its worm-like shape, multiple pairs of stubby legs, and voracious appetite for leaves.
caterpillar-larva
Tomato Hornworm
A large, thick green caterpillar with diagonal white stripes and a distinctive curved horn at its tail end, often found stripping leaves from tomato plants in gardens.
caterpillar-larva
Io Moth Caterpillar
A bright lime-green caterpillar bristling with clusters of branching, stinging spines and thin red and white racing stripes along its sides.
caterpillar-larva
Luna Moth Caterpillar
A large, plump, apple-green caterpillar with faint yellow side stripes and rows of small red-orange tubercles, the larval form of one of North America's most beautiful giant silk moths.
caterpillar-larva
Fall Armyworm
A brownish-green caterpillar marked with a pale inverted "Y" on its head, notorious for rapid, large-scale outbreaks that devastate corn and other grass crops across the globe.
caterpillar-larva
Corn Earworm
A color-variable caterpillar, ranging from pale green to reddish-brown, that burrows headfirst into corn ears and is one of the most economically significant crop pests in North America.
caterpillar-larva
Black Swallowtail Caterpillar
A striking green caterpillar banded with black and dotted with yellow spots, famous for the bright orange, forked osmeterium it flicks out when disturbed.
caterpillar-larva
Mealworm
A tan, segmented larva with a shiny hard exoskeleton that tunnels through stored grain and flour before transforming into a darkling beetle.
caterpillar-larva
Mourning Cloak Caterpillar
A gregarious, velvety black caterpillar speckled with white dots and a striking row of brick-red spots down its back, often seen feeding in clusters on willow branches.
caterpillar-larva
Question Mark Caterpillar
A spiny, variably colored caterpillar named for the silver question-mark-shaped mark on the underside of the adult butterfly's wings.
caterpillar-larva
Gulf Fritillary Caterpillar
A vivid burnt-orange caterpillar bristling with rows of branched black spines that specializes almost exclusively on passionflower vines.
caterpillar-larva
Tussock Moth Caterpillar
A boldly tufted caterpillar bristling with dense brush-like hair tussocks and long dark pencil plumes that give it an almost punk-rock silhouette.
caterpillar-larva
Tiger Swallowtail Caterpillar
A smooth green caterpillar with a swollen thorax marked by two large fake eyespots, giving it an uncanny resemblance to a tiny snake's head.
caterpillar-larva
Polyphemus Moth Caterpillar
A plump, apple-green giant silk moth larva with rows of silvery spots that swells to the size of a large finger before spinning a papery brown cocoon.
caterpillar-larva
Cecropia Moth Caterpillar
North America's largest native caterpillar, a bulky blue-green giant studded with rows of bright red, yellow, and blue knobby tubercles resembling tiny coral formations.
caterpillar-larva
Puss Caterpillar
A caterpillar disguised as a tuft of soft fur, its dense coat of silky hairs conceals rows of spines beneath, making it one of the most deceptively harmless-looking stinging caterpillars in North America.
caterpillar-larva
Eastern Tent Caterpillar
A fuzzy, blue-flecked caterpillar with a pale stripe down its back, famous for spinning large communal silk tents in the forked branches of cherry and apple trees each spring.
caterpillar-larva
Cotton Bollworm
A variably colored caterpillar, ranging from green to brown to nearly pink, that burrows into cotton bolls, corn ears, and tomato fruit, feeding concealed inside the very structures it damages.
caterpillar-larva
Spicebush Swallowtail Caterpillar
A bulging-eyed green caterpillar that lives folded inside its own silk-stitched leaf tent, looking every bit like a miniature snake peering out from cover.
caterpillar-larva
Painted Lady Caterpillar
A spiky, mottled caterpillar that spins loose silk webbing over thistle or mallow leaves and hides inside its own protective tent while feeding.
caterpillar-larva
Eastern Black Swallowtail Caterpillar
A striking green-and-black banded caterpillar dotted with yellow spots that flashes a bright orange forked horn when disturbed.
caterpillar-larva
Armyworm
A striped, greenish-brown caterpillar that gets its name from its habit of migrating in dense, destructive groups across grass and grain fields.
caterpillar-larva
Tobacco Hornworm
A large, chunky green caterpillar with diagonal white stripes and a curved red-orange horn at its tail end, often found stripping tomato and tobacco plants.
caterpillar-larva
Cabbage White Caterpillar
A velvety, bright green caterpillar with a faint yellow stripe down its back, the larval stage of the common white butterfly seen fluttering around vegetable gardens.
caterpillar-larva
Gypsy Moth Caterpillar (Spongy Moth)
A bristly, blue-and-red-spotted caterpillar that can strip entire hardwood forests bare during major outbreak years.
caterpillar-larva
Cabbage Looper
A pale green caterpillar with thin white stripes that arches its back into a loop as it inches along cabbage and other garden leaves.
caterpillar-larva
Saddleback Caterpillar
An unmistakable stout caterpillar with a bright green saddle-shaped patch on a brown back, bristling with clusters of spines along its stocky body.
caterpillar-larva
Inchworm
A slender, twig-mimicking caterpillar that travels by looping its body into an arch and releasing a strand of silk to drop and dangle at the slightest disturbance.
caterpillar-larva
Maggot
A pale, legless, tapering grub that wriggles through rotting food and organic waste, the larval stage of a fly.
caterpillar-larva
Giant Leopard Moth Caterpillar
A jet-black, bristly caterpillar that curls into a tight ball to reveal bright red-orange bands between its segments when disturbed.
caterpillar-larva
Buck Moth Caterpillar
A dark, spiny caterpillar covered in branched spines that marches across oak-lined sidewalks in dense groups each spring.
caterpillar-larva
Pipevine Swallowtail Caterpillar
A dark, velvety caterpillar studded with fleshy orange-tipped tubercles that feeds exclusively on pipevine, storing its host plant's chemistry for later defense as a butterfly.
caterpillar-larva
Codling Moth Larva
The classic 'worm in the apple,' this pinkish-white caterpillar tunnels straight to the core of apples and pears, leaving a telltale frass-plugged entry hole behind.
caterpillar-larva
Zebra Longwing Caterpillar
A creamy-white caterpillar dotted with black spots and armed with branching black spines, feeding exclusively on passionflower vines whose chemistry it stores for defense.
caterpillar-larva
Bollworm
One of the most economically significant caterpillars in North American agriculture, the bollworm changes color from green to brown to pink across its life and bores into cotton bolls, corn ears, and tomato fruit alike.
caterpillar-larva
Sod Webworm
A dull, grayish-green caterpillar that hides in silk-lined burrows by day and emerges at night to chew grass blades down to the thatch.
caterpillar-larva
Parsley Worm
Banded in green, black, and yellow, the parsley worm rears up and flashes a bright orange, forked scent gland when disturbed, a signature defense of black swallowtail caterpillars.
caterpillar-larva
Grape Leaffolder Caterpillar
This small green caterpillar stitches grape leaves together with silk into a rolled shelter, feeding hidden inside its own leafy tube and leaving skeletonized patches behind.
caterpillar-larva
Waxworm
A soft, cream-colored grub found tunneling through beeswax comb, the waxworm is the larva of the wax moth and has become a household staple as fishing bait and reptile feed.
caterpillar-larva
Forest Tent Caterpillar
Named for the silk mats rather than tents it spins, this blue-gray caterpillar sports a row of pale keyhole- or footprint-shaped spots down its back and can appear in outbreak numbers that strip entire stands of trees bare.
caterpillar-larva
Silkworm
Plump, pale, and utterly dependent on humans, the silkworm is the domesticated caterpillar behind thousands of years of silk production, spinning a single continuous thread of silk to form its cocoon.
caterpillar-larva
Stinging Rose Caterpillar
A boldly striped slug caterpillar in candy-like tones of yellow, orange, and purple, crowned with tufted spine clusters that can sting on contact.
caterpillar-larva
Bristly Rose Slug
Despite its caterpillar-like, slug-shaped body covered in fine bristles, this pale green larva is actually the offspring of a small sawfly and feeds on rose leaves by skeletonizing them from the underside.
caterpillar-larva
American Dagger Moth Caterpillar
A pale, sulfur-yellow to cream fuzzball bristling with dense tufts of hair and long black 'pencils' projecting from both ends, the American dagger moth caterpillar is one of the most recognizable hairy caterpillars on hardwood trees in fall.
caterpillar-larva
Spiny Oak-slug Caterpillar
A tiny, flattened slug-shaped caterpillar in shades of green, orange, or purple, bristling with clusters of branched spines that can deliver a sting if handled.
caterpillar-larva
Hag Moth Caterpillar (Monkey Slug)
One of the strangest caterpillars in North America, with curling, hair-covered arm-like projections that make it look uncannily like a tiny tuft of matted fur or a miniature spider monkey.
caterpillar-larva
Milkweed Tussock Caterpillar
Rows of dense orange, black, and white hair tufts run down the back of this milkweed specialist, whose young larvae feed in tight groups that skeletonize milkweed leaves before dispersing to feed alone.
caterpillar-larva