Egg: Bed bug eggs are white and oval-shaped.
1st Stage: Nymphs start out very small - under 2 mm long.
2nd Stage: After its first molt, the nymph is around 2 mm long.
3rd Stage: Usually averages 2.5 mm long in this stage.
4th Stage: Nymph is around 3 mm long.
5th Stage: Typically around 4.5 mm in the final stage.