What kind of larvae are these?
I think that it is termites larvae. For more info check this :  Termites follow the typical life cycle of insects that have a gradual life cycle: they begin as eggs, and then enter nymphal to adult stages. In termite development, newly hatched termites are sometimes referred to as “larvae,” which is not to be confused with the larvae of complete metamorphosis insects like flies.

Termite larvae typically hatch within a few weeks. They are approximately the same size as the eggs from which they hatched and are immediately tended to by worker termites. They often comprise a large part of a termite colony.

Similar to other insect young, termite larvae go through a series of molts, during which they shed their skins. From the larval stage, termite larvae may evolve into other members of the colony’s castes.

If you suspect you have termite activity in or near your home, contact a pest control professional. Termite damage can go undetected and result in significant financial loss from their damage. A termite inspector can inspect a home for signs of activity and conditions that are attractive to termites. They also can offer services to treat and protect the home from potential future damage.