Adult bed bugs grow to between 4 to 5 millimeters in length and 2 to 3 millimeters wide, which is about the size of a small grain of rice. They are oval shaped and brown in color, though bugs that have recently fed have translucent red abdomens.
Bed bugs are elusive, mostly nocturnal insects that feed on blood. True to their name, they are mostly found in or near beds or bedding, usually keeping out of sight except for the few hours at night when they feed. The bite of the bed bug leaves a small red weal, often mistaken for a spider bite. They lay sticky pinhead-sized eggs that adhere to mattresses and other surfaces. Other signs of infestation include tiny red and brown stains and bits of cast-off skin from moulting.