Chigger

The term originated as a corruption of the name of the chigoe flea, a tropical flea common in South America and the West Indies. The breeding females burrow into exposed skin and lay eggs, causing strong irritation and itching. If left inside the skin this may lead to infection or other dangerous complications.

The term is also used to refer to larvae of certain mites which bury themselves in exposed skin in order to feed on the blood of their host. Unlike the chigoe flea, these mites may be either male or female, and do not lay eggs inside their host. This usage, especially common in the United States, likely originated as a misidentification of the mites as chigoes, due to their similar burrowing behavior. However, it has become widespread enough that it is now generally considered a correct usage of the term.