A species of botfly (found only in Central and South America) captures a mosquito and lays its eggs on it ... about 30 of them. The botfly then releases the mosquito. Eventually the mosquito lands on a person. The warmth causes the eggs to hatch, and the larvae (or maggots) fasten to the person's skin.

http://www.worsleyschool.net/science/files/bot/fly.html

Where is Dermatobia hominis found?

The human bot fly is a forest fly, a pest of Central and South America from Mexico south. Though D. hominis infests cattle more often than it does people, and people who live and work near cattle are at higher risk, it’s not uncommon for tourists from North America and other parts of the world to acquire a few warble fly larvae while on vacation.

How do you get human bot fly larvae?

The adult female D. hominis has a curious way of depositing her eggs. Not a bloodsucking insect herself—in fact, she does not feed at all—she captures a bloodsucking insect of a different species and attaches her eggs to the belly of her captive before releasing it. Various bloodsucking species are suitable. Later, when the insect carrying the eggs bites a warm-blooded animal, the eggs hatch and larvae emerge.

With in an hour of hatching, D. hominis larvae penetrate the skin of the host, either through the bite wound, or through intact skin. They don’t travel about once they are inside, but set up a little cavity in which they rest and feed, with a tiny opening to the outside air. The larvae grow larger over a period of up to six weeks.

http://insects.suite101.com/article.cfm/dermatobia_hominis_warble_fly

Stories:

You can normally tell if its a bot fly from the breathing hole in the skin that the bot fly needs in order to be able to breathe.

It is typically a very clean pin head hole, I used to do a few extractions of Bot flys from the British military when they came out to the island from the jungle, they had all kinds of pretty gross things from being stuck in the Jungle day and night for weeks on end.

Anyway to get the bot larvae out alive we used to take a Coke bottle and light a cigarette take a few puffs of the cig and blow the smoke into the bottle, once the bottle was full we would hold it over the breathing hole and wait for the larvae to come to the surface of the hole in order to get some fresh air, once it poked its head out we would get the squaddie up against the wall and 2 to 3 of us would put our thumbs around the perimeter of the hole and push as hard as we could.

I tell you we had to push hard but eventually this big hairy maggot came out pretty disgusting.

Once it was out we put it in a clear film canister for the Limey to take with him, disinfected the area and he went on his way.

http://ambergriscaye.com/pages/town/botfly.html

From Associated Press

July 18, 2007 9:28 PM EDT

CARBONDALE, Colo. - Doctors thought the strange, bleeding bumps on Aaron Dallas' head might be from gnat bites or shingles. Then the bumps started moving.

A doctor found five active bot fly larvae living beneath the skin atop Dallas ' head.

"I'd put my hand back there and feel them moving. I thought it was blood coursing through my head," Dallas told the (Glenwood Springs) Post Independent.

"I could hear them. I actually thought I was going crazy."

Dallas said he likely received the larval infestation while on a trip to Belize this summer. Bot fly infections are not uncommon in parts of Central and South America .

Adult bot flies are hairy and look like bees, without bristles. The larvae, which are about one-third the size of a penny, were living in a pit 2- to 3- millimeters wide. They were removed Thursday.

"It was weird and traumatic," said Dallas , of Carbondale . "I would get this pain that would drop me to my knees."

After a specialist told him he might have shingles, Dallas tried different creams and salves. But the pain only got worse.

"When I saw him again, it was pretty obvious something else was going on," said Dr. Kimball Spence, who could see the spots moving on Dallas' head. "There's an open pit. You see a little activity, not necessarily the larvae, but a fluctuation of the fluid in the pit."

Dallas' wife, Midge Dallas, teased him about it.

"I told him, 'I will love you through your maggots,'" she told the newspaper.

But Dallas saw little to laugh about.

"It's much funnier to everyone else," he said. "It makes my stomach turn over. It was cruel."

http://www.simplyfrogg.com/index49.shtml