A brown bug with long antennae is most likely one of five common insects: a brown marmorated stink bug, a western conifer seed bug, a cockroach, a longhorn beetle, or a camel cricket. Each has a distinct body shape that makes identification straightforward once you know what to look for. Here’s how to tell them apart and what to do about them.
Brown Marmorated Stink Bug
This is the most common culprit when people find a brown, long-antennaed bug indoors during fall and winter. Adults are about 15mm long (roughly the size of a dime) with a wide, shield-shaped body that’s mottled brown. The key identification feature is the banding pattern: both the antennae and the edges of the abdomen have alternating light and dark stripes. If you see those stripes, you’ve almost certainly found a stink bug.
Stink bugs enter homes in large numbers starting in September and October, clustering on exterior walls before finding their way inside through cracks and gaps. They don’t bite, don’t reproduce indoors, and don’t damage your home. They do, however, release a pungent odor when crushed or disturbed, which is why vacuuming them up (or gently relocating them outside) is a better approach than squishing them.
Western Conifer Seed Bug
Often mistaken for a stink bug, the western conifer seed bug is longer and narrower, reaching about 19mm (3/4 inch). It shares the mottled brown coloring but has a few distinguishing features: a dark “X” pattern across its back where the wings overlap, flared or flattened sections on the hind legs (almost leaf-shaped), and alternating dark and light markings along the outer edges of its body. If the bug looks like a stretched-out stink bug with fancy hind legs, this is your match.
Like stink bugs, conifer seed bugs are harmless home invaders that come inside seeking warmth. They feed on the sap and seeds of conifer trees, not on anything in your house. They can also produce a mild odor, though it’s less intense than a stink bug’s.
Cockroaches
Cockroaches have long, threadlike antennae that can be as long as or longer than their bodies, and their flat, oval shape is hard to miss. Two brown species show up most often indoors.
The German cockroach is small, only about half an inch (14mm) long, and light brown with two dark parallel stripes running lengthwise behind its head. It’s the most common indoor cockroach worldwide and strongly prefers kitchens and bathrooms. If you’re seeing small brown bugs with long antennae near food or moisture, this is the likely species, and finding one usually means more are hiding nearby.
The American cockroach is much larger, reaching about 1.5 inches (38mm), and is reddish-brown with a yellowish, roughly M-shaped marking behind its head. It has long wings that cover its abdomen and can fly short distances. These tend to live in basements, drains, and other damp areas. Unlike most other brown bugs on this list, cockroaches are a genuine sanitation concern because they can spread bacteria as they move across surfaces.
Longhorn Beetles
If the bug has a hard, elongated body and antennae that seem disproportionately long relative to its size, you may be looking at a longhorn beetle. One common species, the velvet longhorned beetle, has a body about half to three-quarters of an inch long (12 to 20mm) that ranges from dark brown to brownish-orange. Its antennae are segmented and roughly three-quarters the length of its body. Fine, irregularly distributed hairs give the wing covers a slightly velvety look with lighter-colored patches.
Longhorn beetles are wood-boring insects. They’re typically found near trees, firewood, or wooden structures rather than deep inside a home. If one shows up indoors, it likely hitchhiked in on firewood or lumber. They don’t bite people and aren’t a household pest in the traditional sense, though some species can damage untreated wood.
Camel Crickets
Camel crickets look nothing like a typical cricket. They have a humped, arched back (hence the name), no wings, long spindly legs, and antennae that are dramatically longer than their bodies. Their coloring is a muted brown camouflage pattern, and their overall appearance often leads people to describe them as a cross between a spider and a cricket. They’re also called cave crickets or spider crickets.
You’ll find them in dark, damp spaces: basements, crawl spaces, garages, and utility rooms. They’re completely harmless to people. They don’t bite, don’t chirp, and don’t carry disease. They are, however, impressive jumpers, which can be startling when you encounter one unexpectedly. Reducing moisture in your basement or crawl space is usually enough to make them move on.
One Brown Bug That Can Be Dangerous
Most brown bugs with long antennae are nuisance insects at worst, but there’s one exception worth knowing about. Kissing bugs are brown to dark brown, roughly three-quarters of an inch long, and have thin antennae. They’re most common in the southern and southwestern United States. Unlike stink bugs or seed bugs, kissing bugs feed on blood, typically biting people at night around the face and mouth.
The bite itself is usually painless, but kissing bugs can carry the parasite that causes Chagas disease. The parasite isn’t transmitted through the bite directly. Instead, it’s present in the bug’s feces, which can enter the body through the bite wound or mucous membranes. In parts of Arizona and California, kissing bug bites can also trigger severe allergic reactions, including anaphylaxis. Kissing bugs are distinct from other predatory “assassin bugs” in the same insect family, which have thicker mouthparts, eat other insects, and can deliver a very painful (but not disease-carrying) bite.
If you suspect you’ve found a kissing bug, the Texas A&M Kissing Bug Identification program accepts submissions and can confirm whether the specimen is a kissing bug and whether it carries the Chagas parasite.
How to Keep These Bugs Out
Prevention works better than any reactive approach. The goal is to seal the gaps these insects use to enter your home. On wood-sided homes, caulking cracks and crevices on the exterior is effective. Vinyl siding is trickier because panels are loosely fastened to allow for expansion and contraction, so caulk alone won’t fully block entry. In that case, sealing interior openings around outlet boxes, switch plates, ceiling fixtures, and heat ducts can at least keep bugs trapped in the walls rather than entering your living space.
For bugs already inside, a vacuum works well for stink bugs and seed bugs. You can also use a simple light trap, since both species are attracted to light. If you notice clusters of stink bugs on your home’s exterior in September or October, spraying them off with a strong jet of water and dropping them into a bucket of soapy water can reduce the number that make it indoors later in the season.
For cockroaches, the approach is different. German cockroaches in particular reproduce quickly indoors, so finding even a few warrants a more aggressive response: eliminating food and water sources, sealing entry points around pipes and drains, and using bait stations. For camel crickets, a dehumidifier in the basement is often the simplest fix.