Escamoles are the larvae of ants of the genus Liometopum, harvested from the roots of the agave (tequila) or maguey (mezcal) plant in Mexico. In some forms of Mexican cuisine, escamoles are considered a delicacy and are sometimes referred to as "insect caviar". They have a cottage cheese-like consistency and taste buttery, yet slightly nutty.
During my stay in Mexico City in September 2012, I had the chance to taste delicious escamoles at Restaurante El Cardenal.
For reference and more information: Escamol on Wikipedia