A bed bug’s appearance actually depends on the stage of life it occupies.  Adult bugs tend to have a reddish-brown coloration and are flat and oval-shaped.  They will have no rear wings at all and their front wings will appear to be truncated into structures that resemble pads; this is because the front wings are vestigial in nature.

The abdomen of the adult bed bug is segmented and has microscopic hairs growing on it.  This produces a “banded” appearance when viewed under magnification.

Bed bugs in the nymph stage, in contrast, tend to be almost clear in appearance; certainly they are much lighter in color.  As they move through successive moltings their appearance will darken until it reaches the characteristic darker shade associated with maturity.

Bed bugs are frequently confused with other insects at first glance.  They bear a passing resemblance to both carpet beetles and book lice.