Sometimes maggots inhabit the walls of a home when they find a rotting food source in the wall. You have a pair of options for killing maggots inside your house without calling an exterminator. You can spray the area around the wall with a chemical pesticide toxic to maggots, or you can place a beer trap near the wall and lure the maggots out to their demise.
Obtain a chemical pesticide that contains a maggot toxin. Permethrin and pyrethrum are the two primary types of pesticides that are capable of killing maggots. You may wish to use a pyrethrum-based pesticide if possible because permethrin can be toxic to cats, small animals and children. Pyrethrum is also mildly toxic. If you prefer a non-toxic pesticide you can try Safe Solution's Enzyme Cleaner, a biodegradable and non-toxic pesticide alternative.
Pour the insecticide into a one quart-sized insecticide sprayer.
Spray the area of the wall that is infested with maggots. Spray around any baseboards, cracks and other surfaces that provide access to the infested wall.
Place a tin pan, or some other shallow dish, near the surface through which the maggots access the wall.
Fill the pan halfway with beer.
Place a lamp or other light source above the pan. The light will draw the maggots to the trap, and they will drown in the beer.