How Big Are Lice? Let me divide them into their 3 basic phases
Eggs-glued to a hair shaft. Can be confused with dandruff they are so small
Nymphs-Between size of an egg and adult
Adults-Size of a sesame seed
They live right on the scalp so they are hard to see and hard to detect. Comparing it to a blow up picture of a dime, a nymph could fit on the ear of the picture of FDR on the dime.