They sent their friend the mosquito [xan] ahead of them to
find out what lay ahead. "Since you are the one who sucks
the blood of men walking along paths," they told the mosquito,
"go and sting the men of Xibalba." The mosquito flew
down the dark road to the Underworld. Entering the house of
the Lords of Death, he stung the first person that he saw...

The mosquito stung this man as well, and when he yelled, the
man next to him asked, "Gathered Blood, what's wrong?" So
he flew along the row stinging all the seated men until he
knew the names of all twelve.
[ Popul Vuh, as translated by Ralph Nelson ]