The larva, maggot, and dung worm form a chain of related monsters added in SLASH'EM.
A larva can grow up (down?) into a maggot, w. Unlike a larva, a maggot is neither poisonous to eat nor do they provide sleep resistance. They are also significantly smaller, weighing only 10 and also providing only 10 nutrition.
A larva can grow up into a dung worm, w, the final stage of the SLASH'EM worm growth chain. They are identical to the younger maggot apart from doing 1d4 damage instead of 1d3 and having a higher base level.