Bed bugs are small, but most people can see them with the naked eye. Bed Bugs tend to be somewhat flat and oval shaped. Recently fed bed bugs are swollen, rounded, and elongated but they generally stay hidden when digesting their food (blood).
Content developed by Dr. Susan C. Jones, Professor of Entomology, The Ohio State University.
Bed bugs have three distinct life stages: egg, nymph and adult. After emerging from the egg, a young bed bug goes through 5 nymph stages before its final molt to the adult stage. Adult insects no longer molt.
Adults: An unfed adult bed bug is about a fifth of an inch long (4-5 mm), which is approximately the size of an average apple seed. Adults typically are dark brown, but they may be somewhat red and elongated soon after consuming a blood meal.