Bugs That Bite: Common Biting Bugs
These are the common bugs that can bite people. This guide covers 20 of them.
Quick list
How to narrow it down
Narrow it down with three quick checks. Count the legs: insects have six, spiders and ticks have eight, and centipedes and millipedes have many more. Check for wings, even folded ones. Then compare size against a coin: a US penny is 19 mm across. Our bug identifier tool does this filtering for you.
The 20 bugs
American Dog Tick
American Dog TickDermacentor variabilisA brown tick with ornate white-gray markings on its shield, common along trails, roadsides and grassy fields. It readily feeds on dogs and people.
Tell-tale sign: Brown body with silvery-white mottling on the shield. Risk: American dog ticks can transmit Rocky Mountain spotted fever and tularemia.
Black Widow Spider
Black Widow SpiderLatrodectus mactansA shiny black spider with a red hourglass on the underside of its round abdomen. It builds messy, tangled webs in woodpiles, sheds, meter boxes and outdoor furniture.
Tell-tale sign: Glossy black, globe-shaped abdomen. Risk: Females have venom that can cause severe muscle pain and cramps; seek medical care after a bite.
Blacklegged Tick
Blacklegged TickIxodes scapularisAlso called the deer tick, a small tick with a dark shield and, in adult females, a reddish-orange rear body. It waits on grass and brush to latch onto passing people and animals.
Tell-tale sign: Dark black legs and shield. Risk: Blacklegged ticks transmit Lyme disease, anaplasmosis and babesiosis; remove attached ticks promptly.
Brown Recluse Spider
Brown Recluse SpiderLoxosceles reclusaA tan to brown spider with a dark violin-shaped mark on its back and only six eyes. It hides in boxes, closets and unused clothing in the south-central US.
Tell-tale sign: Dark violin-shaped mark pointing toward the abdomen. Risk: Most bites are mild, but some cause a spreading wound that needs medical care.
Kissing Bug
Kissing BugTriatoma sanguisugaA cone-nosed assassin bug with orange-red markings around the edge of its flat abdomen. It feeds on the blood of animals and people, sometimes biting near the face at night.
Tell-tale sign: Elongated, cone-shaped head. Risk: Kissing bugs can carry the parasite that causes Chagas disease; save the bug and contact your health department if you are bitten.
Lone Star Tick
Lone Star TickAmblyomma americanumAn aggressive, reddish-brown tick of the Southeast and East; adult females have a single white spot on the back. All life stages bite people.
Tell-tale sign: Single white dot on the back of adult females. Risk: Lone star tick bites are linked to ehrlichiosis and alpha-gal syndrome, a red meat allergy.
Mosquito
MosquitoCulicidae (e.g. Aedes albopictus)A small, slender fly whose females bite to take blood for egg production. The Asian tiger mosquito is black with white stripes and bites aggressively during the day.
Tell-tale sign: Long, needle-like mouthpart (proboscis). Risk: Mosquito bites itch and, depending on the region, can transmit West Nile, dengue and other viruses.
Red Imported Fire Ant
Red Imported Fire AntSolenopsis invictaA small, aggressive reddish-brown ant that builds dome-shaped mounds of loose soil in sunny lawns and fields across the southern US. When disturbed, workers swarm and sting repeatedly.
Tell-tale sign: Mixed sizes of copper-red workers in one colony. Risk: Fire ant stings burn, form white pustules, and can cause severe allergic reactions in sensitive people.
Bed Bug
Bed BugCimex lectulariusA flat, oval, apple-seed-sized insect that hides in mattress seams, bed frames and furniture and feeds on human blood at night. Infestations spread through luggage, used furniture and shared walls.
Tell-tale sign: Flat, oval, reddish-brown body without wings. Risk: Bed bug bites itch and cause stress and sleep loss, but bed bugs are not known to spread disease.
Cat Flea
Cat FleaCtenocephalides felisThe most common flea on both cats and dogs, a tiny, flattened, dark insect that jumps huge distances. Eggs drop off pets into carpets and bedding.
Tell-tale sign: Tiny, reddish-brown to black body flattened side to side. Risk: Flea bites itch, can cause allergic dermatitis in pets, and fleas can pass tapeworms.
Chigger
ChiggerTrombiculidae familyThe nearly invisible red larva of a harvest mite that attaches to skin in grassy, brushy areas. Chiggers feed on skin cells, not blood, and cause intensely itchy red bumps.
Tell-tale sign: Microscopic red or orange specks, barely visible. Risk: Chigger bites itch for days, but in the US chiggers don't transmit disease.
Head Louse
Head LousePediculus humanus capitisA tiny, wingless insect that lives only on the human scalp and feeds on blood. Its eggs, called nits, are glued firmly to hair near the scalp.
Tell-tale sign: Sesame-seed-size tan or grayish insect on hair. Risk: Head lice are itchy but don't spread disease; they spread mainly by head-to-head contact.
Horse Fly
Horse FlyTabanus spp.A large, stout fly with huge eyes that pursues people, horses and cattle for blood. Females slice skin with blade-like mouthparts, causing a sharp, painful bite.
Tell-tale sign: Large, heavy body with very large, often iridescent eyes. Risk: Horse fly bites are painful and can swell; they rarely transmit disease to people in the US.
Wheel Bug
Wheel BugArilus cristatusA large, gray assassin bug with a raised, toothed crest on its back that looks like half a gear wheel. It hunts caterpillars and beetles and is a garden ally.
Tell-tale sign: Semicircular, cog-like crest on the thorax. Risk: Its bite is extremely painful and can take days or weeks to heal, so avoid handling it.
Wolf Spider
Wolf SpiderLycosidae familyA large, hairy, fast-running spider that hunts on the ground instead of building webs. Females carry their egg sacs and then their spiderlings on their backs.
Tell-tale sign: Hairy brown or gray body with dark stripes. Risk: Wolf spiders can bite if handled, causing pain and swelling like a bee sting, but they're not dangerous.
Asian Lady Beetle
Asian Lady BeetleHarmonia axyridisAn imported lady beetle that ranges from pale orange to red with anywhere from zero to 19 spots. In fall it gathers in large numbers on sunny walls and slips indoors to spend the winter.
Tell-tale sign: Orange to red dome-shaped body with a variable number of spots. Risk: They can give a mild pinch and release a yellow, smelly fluid that stains, but they carry no disease.
Carpenter Ant
Carpenter AntCamponotus pennsylvanicusA large black ant that nests in moist or damaged wood, including window frames, decks and wall voids. It doesn't eat wood but excavates smooth galleries and pushes out sawdust-like debris.
Tell-tale sign: Large ant with an evenly rounded, single-arch thorax. Risk: Carpenter ants can deliver a painful bite and weaken wood over time, but they do not carry disease.
Hobo Spider
Hobo SpiderEratigena agrestisA brown funnel-web spider of the Pacific Northwest that builds sheet webs with a funnel retreat in window wells, basements and woodpiles. Males wander indoors in late summer and fall.
Tell-tale sign: Brown body with a herringbone pattern on the abdomen. Risk: Hobo spiders were once blamed for dangerous bites, but current research does not show they cause necrotic wounds.
House Centipede
House CentipedeScutigera coleoptrataA fast, yellowish-gray centipede with 15 pairs of very long legs that races across floors and walls at night. It hunts silverfish, cockroaches and spiders.
Tell-tale sign: Fifteen pairs of long, banded legs. Risk: House centipedes rarely bite; a bite feels like a mild bee sting.
Southern House Spider
Southern House SpiderKukulcania hibernalisA velvety, dark gray to brown spider of the southern US whose males look like brown recluses. Females build radiating, lint-like webs around cracks in walls and windows.
Tell-tale sign: Velvety, uniformly dark females with a small head. Risk: Southern house spiders rarely bite and are not medically significant.
Which ones should you worry about?
15 of the 20 bugs in this guide can bite or sting. The ones to take seriously are American dog tick, black widow spider, blacklegged tick, brown recluse spider, kissing bug, lone star tick, mosquito and red imported fire ant. The rest are harmless or simply a nuisance.
Frequently asked questions
What is the most common one?
Among the bugs in this guide, the American dog tick and black widow spider are the ones people ask about most.
Which of these are dangerous?
American Dog Tick, Black Widow Spider, Blacklegged Tick, Brown Recluse Spider, Kissing Bug, Lone Star Tick, Mosquito and Red Imported Fire Ant can be medically significant.
How can I identify a bug I found?
Use the free bug identifier tool: choose the number of legs, wings, main color, size and where you found it, and it will list the closest matches.