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Identification

Bugs in the Yard and Patio: 13 Types and What to Do

By the Bug Identifier Editorial Team. Updated September 27, 2026. 5 minute read.

Bugs in the Yard and Patio are one of the most common identification questions we get. Here are 13 you are likely to see.

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 13 bugs

Arizona Bark Scorpion

Arizona Bark ScorpionCentruroides sculpturatus50–80 mmHealth risk

A slender, light tan scorpion of the desert Southwest and the most venomous scorpion in North America. It climbs walls and ceilings and often hides in shoes, bedding and clothing.

Tell-tale sign: Thin, light yellowish-tan body and slender pincers. Risk: Bark scorpion stings cause severe pain and numbness and can be dangerous for young children and older adults; call Poison Control at 1-800-222-1222 after a sting.

Bald-Faced Hornet

Bald-Faced HornetDolichovespula maculata15–20 mmHealth risk

A black wasp with ivory-white markings on its face and the tip of its abdomen. It builds large, gray, football-shaped paper nests in trees, shrubs and under eaves.

Tell-tale sign: Black body with a white face and white tail markings. Risk: Bald-faced hornets deliver painful stings and attack in numbers when their nest is disturbed.

Black Widow Spider

Black Widow SpiderLatrodectus mactans3–13 mmHealth risk

A 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.

European Hornet

European HornetVespa crabro25–35 mmHealth risk

The only true hornet established in North America, a large brown-and-yellow wasp that nests in hollow trees, barns and wall voids. It often flies at night and is attracted to lights.

Tell-tale sign: Large wasp with a reddish-brown head and thorax. Risk: European hornet stings are very painful, and colonies defend their nest, though workers are less aggressive away from it.

Kissing Bug

Kissing BugTriatoma sanguisuga15–25 mmHealth risk

A 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.

Mosquito

MosquitoCulicidae (e.g. Aedes albopictus)3–6 mmHealth risk

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 invicta2–6 mmHealth risk

A 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.

Yellowjacket

YellowjacketVespula maculifrons10–16 mmHealth risk

A sleek, bright yellow-and-black wasp that nests underground or in wall voids. Late-summer workers scavenge for sweets and meat and are drawn to picnics and trash cans.

Tell-tale sign: Smooth, shiny yellow and black body with little hair. Risk: Yellowjackets sting repeatedly and defend nests aggressively; multiple stings or an allergy can be dangerous.

Horse Fly

Horse FlyTabanus spp.10–30 mmCan bite or sting

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.

Velvet Ant

Velvet AntDasymutilla occidentalis15–25 mmCan bite or sting

Not an ant at all but a wingless female wasp covered in bright red, velvety hair. It runs across sandy ground in summer and lays eggs in the nests of ground-nesting bees.

Tell-tale sign: Dense, bright red or orange fuzz with black bands. Risk: Its sting is famously painful, earning it the name cow killer, but it is not deadly and it isn't aggressive.

Cicada Killer

Cicada KillerSphecius speciosus30–50 mmNuisance

One of the largest wasps in North America, with a black-and-yellow abdomen and amber wings. Females dig burrows in sandy lawns and stock them with paralyzed cicadas.

Tell-tale sign: Very large wasp up to two inches long. Risk: Despite their size, cicada killers are docile; males can't sting and females rarely do.

Smokybrown Cockroach

Smokybrown CockroachPeriplaneta fuliginosa30–38 mmNuisance

A large, uniformly dark mahogany cockroach common in the humid Southeast. It lives outdoors in tree holes, mulch and gutters and flies toward lights at night.

Tell-tale sign: Shiny, uniformly dark brown body with no markings. Risk: Smokybrown cockroaches can carry bacteria indoors from mulch and garbage.

Spotted Lanternfly

Spotted LanternflyLycorma delicatula20–25 mmNuisance

An invasive planthopper spreading through the eastern US that feeds on grapevines, maples and tree of heaven. Its folded gray forewings hide bright red hind wings.

Tell-tale sign: Gray forewings with black spots. Risk: Spotted lanternflies don't bite or sting; they damage vineyards and leave sticky honeydew.

Which ones should you worry about?

10 of the 13 bugs in this guide can bite or sting. The ones to take seriously are Arizona bark scorpion, bald-faced hornet, black widow spider, European hornet, kissing bug, mosquito, red imported fire ant and yellowjacket. The rest are harmless or simply a nuisance.

Frequently asked questions

What is the most common one?

Among the bugs in this guide, the Arizona bark scorpion and bald-faced hornet are the ones people ask about most.

Which of these are dangerous?

Arizona Bark Scorpion, Bald-Faced Hornet, Black Widow Spider, European Hornet, Kissing Bug, Mosquito, Red Imported Fire Ant and Yellowjacket 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.