Bug Identifier

True Bugs

Bed Bug

Cimex lectularius

0246810
Body length in millimeters. Shaded bar shows the typical adult range.
Scientific nameCimex lectularius
GroupTrue Bugs
Size4–7 mm (up to about 0.28 in)
Colors Brown and Red
Legs6 legs
WingsNo (as usually seen)
Where foundBedroom or bed
Most activeSpring, Summer, Fall and Winter
BitesYes
StingsNo
Risk levelCan bite or sting

How to identify it

The bed bug is a small member of the true bugs group. Piercing, straw-like beaks and wings that overlap in an X on the back. Check for these three features:

  1. Flat, oval, reddish-brown body without wings
  2. Rust-colored stains or tiny black dots on mattress seams
  3. Itchy bites, often in lines or clusters

About this bug

A 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.

You'll usually find bed bugs in bedrooms and beds. They are most active in spring, summer, fall and winter.

Is it dangerous?

Bed bug bites itch and cause stress and sleep loss, but bed bugs are not known to spread disease.

Our rating: Can bite or sting, meaning it can bite or sting, usually with mild, local effects.

When you'll see bed bugs

Bed Bugs are most active in spring, summer, fall and winter. In spring, overwintering adults become active and many species lay their first eggs. Summer heat speeds up development, so populations can grow quickly. In fall, many bugs look for shelter, and some move toward or into buildings. In winter, activity continues mainly indoors in heated spaces.

Typical places to check: bedroom or bed.

About true bugs

The bed bug is one of the true bugs. True bugs have piercing, straw-like mouthparts used to suck plant sap or, in a few species, blood. They develop through gradual metamorphosis: nymphs look like small, wingless adults and molt several times as they grow. Many release strong odors from scent glands when threatened.

Because nymphs look like adults, you'll often see mixed sizes of the same bug together, which is a good sign that a population is breeding nearby.

What to do about it

  1. Inspect mattress seams, headboards and furniture joints with a flashlight
  2. Wash and dry bedding on high heat for at least 30 minutes
  3. Hire a professional for heat or chemical treatment, since DIY rarely eliminates them

Read the full guide: how to get rid of bed bugs.

Bugs that look similar

Varied Carpet BeetleAnthrenus verbasci2–3.5 mmNuisance

Group: Bed Bug belongs to true bugs, while varied carpet beetle belongs to beetles. Piercing, straw-like beaks and wings that overlap in an X on the back.

Kissing BugTriatoma sanguisuga15–25 mmHealth risk

Size: Kissing Bugs are larger, reaching 25 mm, while bed bugs top out around 7 mm.

BooklouseLiposcelis spp.1–2 mmHarmless

Group: Bed Bug belongs to true bugs, while booklouse belongs to centipedes, millipedes & crawlers. Piercing, straw-like beaks and wings that overlap in an X on the back.

Cat FleaCtenocephalides felis1–3 mmCan bite or sting

Group: Bed Bug belongs to true bugs, while cat flea belongs to other insects. Piercing, straw-like beaks and wings that overlap in an X on the back.

Head LousePediculus humanus capitis2–3 mmCan bite or sting

Group: Bed Bug belongs to true bugs, while head louse belongs to other insects. Piercing, straw-like beaks and wings that overlap in an X on the back.

Frequently asked questions

What does a bed bug look like?

Flat, oval, reddish-brown body without wings. Adults measure 4–7 mm (up to about 0.28 in).

Does the bed bug bite or sting?

It can bite. It does not sting. Bed bug bites itch and cause stress and sleep loss, but bed bugs are not known to spread disease.

Where do bed bugs live?

Bed Bugs live in bedrooms and beds.

When are bed bugs most active?

Mostly in spring, summer, fall and winter.