Adult bed bugs are small, wingless insects about the size of an apple seed, typically 5 to 7 mm (3/16 to 1/4 inch) long. They have a flat, oval-shaped body that is reddish-brown in color when unfed, and after feeding, their bodies swell and turn a bright reddish color, becoming more elongated and balloon-like
. Immature bed bugs, called nymphs, are smaller and translucent whitish-yellow or pale in color before feeding. After feeding, nymphs become plump and bright red, making them easier to see. Nymphs go through five stages before reaching adulthood, shedding their skins each time
. Bed bug eggs are tiny, pearl-white, about the size of a pinhead, and may show an eye spot if older than five days
. Key physical features include:
- Six legs and two antennae
- Flat, broad oval shape when unfed; swollen and elongated when fed
- No functional wings, only wing pads
- A musty, sweetish odor produced by glands on the underside of the body
Bed bugs often hide in mattress seams, cracks, crevices, and furniture joints, making them hard to spot unless you look closely
. In summary, bed bugs look like small, flat, reddish-brown oval insects about the size of an apple seed, with nymphs being smaller and paler until they feed
