18 Common House Bugs and How to Identify Them, According to Insect Experts

What it looks like: You’re probably very familiar with this one. Ladybugs are tiny, oval, winged beetles that are usually between 1 to 10 millimeters (mm) in length, depending on the species. They are typically bright red with black spots.

Where you’ll find it: You can find them in your home in autumn between September through November, when the temperatures drop and they seek a warm spot for winter. They like to gather together within crevices, like cracks around windows and door frames, soffits, attics, wall voids, and the area behind fascia boards and exterior siding.

Can it harm you? These beetles are believed to trigger allergies, ranging from eye irritation to asthma, potentially because they emit a stinky, yellow secretion when they feel they’re in danger. Lady bird beetles also can bite (it feels like a pinch), but they are not poisonous and are rarely harmful.

What it looks like: This invasive bug is large, as it can grow up to 2 centimeters long. “When you look at its abdomen from the top, just around where its wings are, you’ll see a marbled pattern on its back,” which is shield-shaped, says Michael J. Raupp, Ph.D., professor of entomology at The University of Maryland and creator of Bug of the Week. A brown marmorated stink bug also has distinct white bands on its antennae and legs, which distinguishes it from other native species that are also brown in color.

Where you’ll find it: You’ll spot these in your home from September through October to find a protective spot as its gets colder. They’ll enter homes via windows, door cracks, vents, siding, shutters, loose siding—you name it. Unfortunately, they congregate in masses, so getting rid of stink bugs can be annoying.

Can it harm you? Besides the pungent odor they give off, stink bugs do not bite humans or pets, but they can do a number on your garden.

What it looks like: Wolf spiders are hunting spiders—and can be pretty big, up to an inch and a half long, Marc Potzler, a board-certified entomologist and technical services manager with Ehrlich Pest Control recently told Prevention. They are usually black, gray, or brown, and have a hairy appearance.

Where you’ll find them: After mating in the fall, female wolf spiders look for protected areas to produce their egg cocoons. You’ll find them under and between boards, stones, firewood, and siding, most commonly in basements, sheds, or garages where other insects are, says Potzler.

Can it harm you? Wolf spiders can bite, but only if they feel threatened. “They would prefer to hide than bite,” according to Howard Russell, M.S., an entomologist at Michigan State University.

What it looks like: These are spindly spiders with long thin legs. The body of the cellar spider is usually 1/4- 5/16-inch-long, with legs extending another 2 inches.

Where you’ll find it: “You’ll always find them in a corner with a cobweb,” says Raupp. Their namesake matches their stomping grounds, including basements, attics, or other protected places. Cellar spiders are known for their webbing, continuously adding to them.

Can it harm you? Cellar spiders are not venomous and not known to bite.

What it looks like: These crickets are light brown, tan, and dark brown with a humped back. They have very long antennae, and their bodies grow between 1/2 to 1 1/2 inches long.

Where you’ll find it: “You’ll find them in the basement or dark mancave,” says Raupp, as they prefer dark, moist places.

Can it harm you? No. Camel crickets do not bite and are not known to be harmful to humans and pets.

What it looks like: When you think of a stereotypical cricket, these are the ones. Adult field crickets are black and brown in color and are between 1/2 to 1 inch long. They have six legs, long antennae, and antennae-like appendages at the end of their abdomens called cerci. They also have hind wings.

Where you’ll find it: They enter buildings through open doors and windows and through cracks in foundations. You’ll likely be able to locate them through their signature chirping.

Can it harm you? No. Field crickets do not bite or carry diseases. However, once indoors, crickets may damage clothing, drapes, or wall coverings—thanks to stains from feces or by their feeding.

What they look like: These black ants are tiny. They grow between 1/16 to 1/8 inch long. When they’re crushed, they release a bad (somewhat sweet) odor, often described as rotten coconut or banana.

Where you’ll find them: Odorous house ants feed on pretty much anything, but are drawn to sweet things. So, you’ll often find them near water and food sources, like garbage cans and kitchen sinks or counters. They also nest indoors near sources of warmth, commonly in wall voids near pipes or heaters.

Can they harm you? Nope, just keep an eye on your groceries.

What it looks like: Carpenter ants are one of the largest ant species in North America. Wingless types grow between ¼ to ½ inch, while those with wings can grow up to 1 inch. They are shiny, usually black or dark brown, and known for their narrow waists. They also have mandibles (jaw-like appendages) used for chomping.

Where you’ll find it: They often damage homes and other wooden structures, so they can be found in moist or decayed wood caused by exposure to water leaks, condensation, or poor air circulation.

Can it harm you? Unfortunately, yes. Carpenter ants can bite, and they’ve been known to break skin when they do, which can be painful. While they don’t use venom, they do inject an irritant called formic acid into the area, which may cause an allergic reaction. The bites usually don’t require medical attention but should be cleaned well to avoid any issues.

What it looks like: These bugs are shaped a bit like a stink bug and grow up to 3/4 inch long. They are a reddish-brown color, and usually have a bright yellow or orange underside with black patches.

Where you’ll find it: Western conifer seed bugs tend to congregate in the fall as they seek shelter for the winter. They can be found around baseboards, window and door moldings, openings for electrical outlets and fixtures, openings for heating or cooling vents, and other similar pathways.

Can it harm you? They do not bite or sting, but can gather in annoyingly large numbers within the home.

What it looks like: While they look similar to your standard house fly, cluster flies are often larger, about ⅓ inch long. They are dull-gray and black and have golden-yellow hairs on their bodies, which give them a golden sheen and bristly texture.

Where you’ll find it: Cluster flies head indoors to outlast the winter. You’ll likely find them in attics, under siding, and around windows and crevices on the outside of buildings. They also congregate between walls and work their way out through openings in window frames and electrical fixtures.

Can it harm you? Cluster flies aren’t venomous and do not bite, don’t lay eggs in food like house flies, and aren’t associated with transmitting diseases.

What it looks like: This creepy crawler get its name from its silvery scales and three, tail-like appendages that protrude from its abdomen. Its antennae is as long as its body and can grow up to 12 mm in length.

Where you’ll find it: Silverfish are known to feed on foods high in starches and destroy books, papers, wallpaper, and more. They are found in high-humidity environments, but are able to survive a wide range of temperatures. They usually hang out indoors in concealed, temperature-controlled areas such as bathrooms, attics, and basements.

Can it harm you? Silverfish do not bite, do not have venom, and are not poisonous if ingested. They are gross, though.

What they look like: An adult bed bug can be anywhere from ⅛ - ¼-inch in size. “They are often compared to the size of an apple seed,” says Nancy Troyano, Ph.D., a board-certified entomologist with Western Exterminator. Bed bugs can range in color from a mahogany-red to light brown, “depending on when they last fed,” Troyano says.

Where you’ll find them: In general, you’ll find them around people. “Blood is their only food source,” says Glen Ramsey, a board-certified entomologist and senior technical services manager at Orkin. Bed bugs are normally nocturnal, and they’ll come out of hiding from places like a mattress to feed on sleeping or quietly resting people. “They can travel from place to place with ease, including items such as luggage, purses, and other personal belongings,” Ramsey says.

Can they harm you? Yes. “While bed bugs have not been found to transmit any diseases to humans, their bites may cause symptoms such as itching, red welts, or swelling the day after being bitten,” Ramsey says. However, “many bites can leave no mark and go completely unnoticed.”

What it looks like: There are different types of cockroaches, but the most common are the American, German, oriental, and brown-banded cockroaches, Ramsey says. “Cockroaches can measure over two inches length, with tropical species tending to be larger than those found in other climates,” Ramsey says. They have six legs, two antennae, and some even have wings. “However, most winged cockroaches are not particularly adept at flying,” Ramsey says.

Where you’ll find it: You can find cockroaches in a lot of places in your home, Troyano says. They could pop up in the bathroom—they love to snack on soap residue—dark places in your kitchen like cupboards and cabinets, laundry rooms, basements, and drains, she says.

Can it harm you? Unless you have a serious infestation, cockroaches won’t bite you. While cockroaches don’t give people diseases through bites, they can transmit food-borne illnesses from one place to another. They can also trigger asthma “because of a protein in their saliva, droppings, and on their body,” Troyano says.

What they look like: Fruit flies look like light brown flies, says Russell. They’re usually very small—about 1/8 of an inch. “There are two main types of fruit flies: the common red-eyed fruit fly and the dark-eyed fruit fly,” Ramsey says.

Where you’ll find them: Fruit flies like to hang out around fruit and produce, especially when it’s ripe, rotting, or decayed, and they’re also attracted to fermented items like beer, liquor, and wine, Ramsey says. “Fruit flies also may breed and develop in drains, garbage disposals, trash cans, and mop buckets,” he adds.

Can they harm you? In general, Russell says that fruit flies “are just a nuisance.” But they have the potential to contaminate your food with bacteria and other pathogens, Ramsey says, which is why it’s so important to store produce in air-tight containers or refrigerators and inspect any fruits or vegetables brought into your home. “Also, establish a schedule to regularly clean drain lines, garbage disposals, and any location where food waste accumulates,” he says.

What it looks like: Centipedes have “long, segmented, generally flattened bodies with one pair of legs per body segment,” Russell says. They also have a pair of venomous fangs they use to take out their prey. Centipedes range from 4 to 152 millimeters in size and usually are brown or a reddish orange color.

Where you’ll find it: “House centipedes live in damp, undisturbed places, such as cellars, closets, bathrooms, and attics,” Troyano says.

Can it harm you? Some types of centipedes will bite “but do not pose a serious threat,” Troyano says. Still, a bite can still lead to some swelling and a little pain in the area.

What it looks like: As perhaps the main insect that really strikes fear in most homeowners, termites can wreak significant havoc in a short amount of time. Per Orkin, they typically measure between 1/4 and 1/2 of an inch long and have soft bodies with straight antennae. The queens and kings are larger, capable of reaching over one inch long. Their colors range from white to light brown, where worker termites often appear lighter and swarming termites darker. Flying termites, also called reproductives, have two pairs of prominent wings.

Where you’ll find it: Although termites often remain unseen behind your walls, you may notice some clues that could indicate a termite issue. These clues might include bubbling paint, mud tubes and discarded wings.

Can it harm you? Known as “silent destroyers,” termites can eat through wood—including the posts and beams that keep your home standing. Although termites cause pose a serious threat to your home, they are not known to attack or bite people and pets, and do not pose any serious health risks.

What it looks like: Earwigs are typically dark red-brown and usually stretch from 5-16 mm. Their key identifier are their pincers on the rear.

Where you’ll find it: Earwigs move into homes to find food or because of a change in weather. They usually wind up indoors while seeking shelter or just happen to wander inside through open doors. Per Orkin, homeowners often find them in areas where there is water—kitchens, bathrooms, and laundry rooms.

Can it harm you? There is a superstition that earwigs burrow into the ears of people while they sleep (don’t worry, that’s just a myth). Earwigs are known to pinch humans when they feel threatened but will rarely do so on purpose. Their pincers may look scary but are not very strong and will rarely break the skin. If you are bit, rest assured that earwig bites are not toxic to humans.

What it looks like: Per Orkin, there are thousands of mite species, the majority of which measure less than 1 mm in length. The most common mite species you’ll encounter are dust mites, clover mites, spider mites, bird mites, or chigger mites. Like other arachnids, their bodies are comprised of the prosoma and abdomen. Mites bear four pairs of legs.

Where you’ll find it: How mites get into the house or yard depends on their species. Clover mites often exploit tiny cracks to enter homes by the thousands. Other types, like dust mites are almost always found inside homes, while chiggers and bird mites attach themselves to hosts and hitchhike into homes on people and pets.

Can it harm you? Yes, these super small pests can do a variety of damage. Mite bites are small and usually not painful, producing only mild skin irritation. However, frequent itching caused by mites may lead to more serious infections. On the other hand, dust mites are one of the most common allergens and can even trigger asthma attacks.