Myrmekes are giant ant-like creatures that are the size of a full grown German Shepherd and love shiny things, such as gold. They live in enormous anthills with complex winding passageways loaded with stolen loot like gold, weapons, and jewellery. They spray poison, have almost unbreakable back armour, have vicious mandibles and can call on the rest of the nest to aid them, and can quickly swarm even the most skilled fighter. Not something a demigod would like to be up against.
During ancient Greek times, people believed them to live in the Indian deserts, where they stocked their ant hills with gold. To explain the riches of the Indian people, legend says that the bravest warriors of the Indians slipped into the ant nests to recover the gold in a deadly game of snatch and grab.
Myrmekes are known to have tough skin and spit acid that tenderizes their prey. Myrmekes means ants in Greek.
During a game of Capture the Flag, a swarm of Myrmekes are seen dragging the head of the Bronze Dragon across the ground to their hive. Charles Beckendorf says that the dragon has been lost for years and tries to take the head back from the giant ants, but is himself captured in the process. Silena Beauregard becomes very upset when she finds out and helps Annabeth Chase fix the Bronze Dragon that had been recently dug up. Once repaired, it charges toward the Myrmekes hive and causes havoc among the ants, allowing Annabeth, Silena and Percy Jackson to rescue Beckendorf.
When Apollo, who was turned into a human named Lester Papadopolous, and Meg McCaffrey go into the Camp Half-Blood Forest to look for the missing camps, they encountered a carcass of a Myrmeke which freaks Meg out. After a conversation with a Palikos named Pete, they are attacked by three Myrmekes. Apollo manages to defeat them by using his ukulele Harley made for him, despite the fact that he swore on the River Styx not to play music or use a bow until he was a god again. But then he realizes that the Myrmekes have kidnapped Meg after the fight. After searching around the forest for Meg, he goes back to the palikos and asks him how to get to the Myrmeke's Lair. Pete finally tells Apollo after also telling him to get treatment at Camp Half-Blood and that Meg has 24 hours before she's killed at the lair.
Apollo does so and grabs a bow also. He then goes into the forest and finds the Myrmekes' lair. He manages to throw the ants off by singing, but eventually is worn out and uses his arrows. Once in the center of it, he finds Meg and they attempt to escape, but are stopped by the queen Myrmeke. Apollo uses the last of his strength to perform a rap appreciating mothers, which sways the queen into letting him go. After making it out of the lair, Apollo and Meg make it to the Grove of Dodona. When the camp is under attack by the Colossus Neronis, Apollo decides have Myrmeke give him a Meg a ride out of the forest.