Lice eggs, also called nits, look like small sesame seeds, and they are attached firmly to the hair. Dead lice eggs stay afixed to the hair and remain in the hair if they're not removed properly.
Since nits cannot live without the heat and humidity of the scalp, according to Living with Bugs, live ones are located very close to the scalp. All eggs that are found more than 1/2 inch from the scalp are either hatched or dead, according to MSN Healthy Living. Dead eggs may appear dull. Some chemical rinses kill live nits in addition to killing the bugs.