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.

Horn Fly
A tiny, dark fly that clusters in dense patches on the backs and shoulders of grazing cattle, using piercing mouthparts to take frequent small blood meals.
flyOnion Fly
A slender gray fly closely related to houseflies whose white legless larvae bore into onion bulbs, feeding in clusters within a single rotting bulb.
flySnipe Fly
A slender, long-legged fly often seen perched head-down on a sunny tree trunk or fence post, patiently watching for smaller insects to ambush. Its tapered, wasp-like abdomen and habit of resting motionless with legs splayed give it a distinctive, almost sentry-like posture in woodland clearings.
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Drain Fly
A tiny, fuzzy gray-tan fly with broad, moth-like wings held tent-fashion over its body, often seen resting motionless on bathroom walls near drains.
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Long-Legged Fly
A jewel-bright little fly that flashes metallic green, blue, or bronze in the sunlight as it darts across leaves on comically long, stilt-like legs, pausing to perform quick territorial displays. Both adults and larvae are active hunters of even smaller insects, making this tiny fly a useful predator in gardens and wetlands alike.
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Screwworm Fly
A metallic blue-green blowfly whose larvae are unusual among maggots for feeding on living tissue rather than carrion, drawn to even small open wounds on warm-blooded animals. The species has been the target of one of the most successful large-scale insect eradication campaigns in history across much of North America.
flyPhorid Fly
A tiny, hump-backed fly best known for scuttling erratically across countertops and floors rather than taking flight, drawn to anything rotting or moist.
flyWarble Fly
A furry, bee-mimicking fly that never lands on flowers or feeds as an adult, spending its brief life darting around grazing cattle to lay eggs on their legs and lower body. Herds sometimes react with sudden panicked runs, known as gadding, whenever a warble fly approaches.
flyCrane Fly Larva
Thick-skinned and worm-like, the crane fly larva, often called a leatherjacket, burrows through wet mud and decaying vegetation at the edges of ponds and streams, breaking down plant material as it grows.
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Black Fly Larva
Anchored to submerged rocks in fast-flowing streams by a silken thread, the black fly larva bends into the current and combs the water for drifting particles with a pair of delicate, fan-shaped feeding brushes.
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Vinegar Fly
A tiny tan fly with bright red eyes that seems to appear out of nowhere the moment a banana starts to spoil, drawn in by the smell of fermentation rather than the fruit itself. Few insects have contributed more to the science of genetics, making this unassuming kitchen visitor one of the most studied animals on Earth.
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Human Bot Fly
A stout, dark-bodied fly from the American tropics famous for an unusual reproductive trick: it captures a blood-feeding mosquito mid-flight and glues its own eggs to the mosquito's body before releasing it to carry them to a future host. The adult itself is rarely seen, spending most of its short life in shaded forest understory.
flySoldier Fly Larva
Flattened, leathery, and tapered at both ends, the soldier fly larva drifts just beneath the surface film of ponds and marshes, filtering algae and organic debris while breathing through a fringe of water-repellent hairs at its tail.
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Blue Bottle Fly
A robust fly with a glossy, metallic blue-black body and a loud buzzing flight, commonly seen around outdoor waste and occasionally indoors, easily recognized by its shiny coloring and bristly frame.
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Fruit Fly (Vinegar Fly)
A tiny tan fly with bright red eyes that seems to appear from nowhere the moment a piece of fruit begins to overripen or a splash of wine is left uncovered.
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Black Soldier Fly
A sleek, dark, wasp-like fly whose larvae are voracious decomposers of decaying organic material, while the short-lived adults do not feed at all.
flyPicture-Winged Fly
A small fly whose clear wings are decorated with bold bands, spots, or intricate patterns, often waved and flicked in slow, deliberate displays that give the impression of a tiny fan being opened and closed. Some species even raise their patterned wings above the body and walk sideways in courtship displays reminiscent of a strutting peacock.
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Fruit Fly (Mediterranean)
A small but strikingly patterned fly with mottled, banded wings held out to the sides in a fan and a body dotted with silvery spots, best known for larvae that tunnel through ripening fruit. Native to sub-Saharan Africa, it has spread with human trade to become one of the most widely recognized fruit-infesting insects in the world.
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Greenhead Fly
A stout, strikingly green-eyed horse fly that emerges from Atlantic salt marshes in midsummer swarms, where the females bite to feed on blood.
flyFungus Gnat
A small, dark, mosquito-like fly with long legs and delicate smoky wings, often seen weakly fluttering around houseplants or crawling across damp potting soil.
flyMaggot
A pale, legless, tapering grub that wriggles through rotting food and organic waste, the larval stage of a fly.
caterpillar-larvaGall Midge
A delicate, mosquito-like fly whose larvae trigger plants to grow strange, often colorful swellings called galls, each species usually tied to one particular host plant.
flyRat-Tailed Maggot
Named for its long, thin, telescoping breathing tube, the rat-tailed maggot is the aquatic larva of the drone fly, thriving in stagnant, low-oxygen water where few other insects can survive.
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Cicada
A stout, big-eyed insect best known for the loud, buzzing chorus of song produced by males, and for periodical species that emerge from the ground by the millions after living underground for over a decade.
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