A species of parasitic insect living primarily in Central or South America. The most notorious of these flies is Dermatobia hominis, the Human Bot Fly. Like other Bot Flies, the Human Bot Fly deposits its larvae inside a hosts' skin, where it forms a protective tumor called a warble and derives nutrition from the host's bloodstream. After six weeks, the larvae punches back out of the skin in pupated form, leaving the warble inside. In this case, the host is a person.
Fortunately, impregnation by a Bot Fly is very unlikely for short term visitor, but any "bite" that a person acquires while in these areas should be promptly investigated. Although not particularly harmful beyond the risk of infection, but that probably doesn't make it any less disgusting.
Bot Fly larvae have one critical weakness while in the warble, which is the need to breathe air. Therefore, a Bot Fly can be recognized in early stages by a small pin hole in your "mosquito bite". The easiest way to remove a Bot Fly larva without medical attention is to fill a soft drink bottle with smoke and then hold it tightly over the opening. The larva will begin to suffocate and partially exit from the warble, allowing the host to squeeze it the rest of the way out. DO NOT PULL on the Bot Fly as it is anchored in with a series of hooks and will simply rip apart, leaving the host with a big mess of bug guts in his flesh and a nasty infection to look forward to.
College Student: Like, ew, I got this totally gross parasite thingy when I was in Cancun. Can you pass me the tweezers?
Adult: Something tells me that Bot Fly wasn't the ONLY thing you picked up in Cancun! And no, you have to PINCH it out, not PULL.