The human bot fly is an insect, dermatobia hominis,
which has an interesting reproductive cycle.
When the female bot fly is ready to lay eggs, she will capture another blood-sucking insect and glue her eggs to its abdomen. Then when that insect feeds, the larvae will hatch and enter the wound. There they develop under the skin, forming painful, swollen lesions. Eventually the larvae emerge
from beneath the skin of their host to continue their lifecycle.
I read somewhere of an interesting cure for bot fly larvae infection. The cure takes advantage of the fact that the bot fly larvae use a kind of snorkel which protrudes a tiny bit above the surface of its host's skin to breathe. To effect the cure, take a piece of raw meat and firmly place it over the lesion, forming an airtight seal. The
bot fly larva will be unable to breathe, and so will burrow
up through the meat until its snorkel protrudes from the
meat's surface. Then throw the meat (and bot fly larva it contains) away (preferably into the fire)...you're cured.
The human bot fly lives in Mexico, Central America, and South America.