small tropical flea; the fertile female burrows under the skin of the host including humans
source: WordNet 3.0
A species of flea (Pulex penetrans), common in the West Indies and South America, which often attacks the feet or any exposed part of the human body, and burrowing beneath the skin produces great irritation. When the female is allowed to remain and breed, troublesome sores result, which are sometimes dangerous. See Jigger.