Occasionally they will move into the sound structural wood of a building. If they are permitted to remain there, serious damage can result.
Wingless forms are large, usually black, ants.
Large numbers of winged forms will emerge from a nest, usually during spring or early summer. They accumulate at windows and doors trying to find new nesting sites. Another sign of infestation is the year-round presence of wingless forms searching for food. They will be attracted to all sorts of animal and vegetable matter. If their presence is seasonal the nest is outdoors and they enter the house in search of food.