Odorous house ants are small ants about 1/8th inch long and dark brown in color. They are found throughout the US, and in spite of their name, are only occasional pests in the house. Their name comes from the disagreeable odor, similar to the smell of rotten coconuts, that is given off when the worker ants are crushed.
Odorous house ants commonly nest outdoors in the soil under stones, logs, mulch, debris and other items. They will also nest indoors in wall and floor voids, particularly in moist or warm areas. If only a few workers (wingless ants) are observed in the house it is an indication that they are nesting outdoors and entering the house in search of food. If winged swarmers are found indoors, or if workers are consistently seen in great abundance, it likely indicates they are nesting within the house.
Control of odorous house ants should begin with an attempt to locate the origin of the ants. Careful and frequent observation may be necessary to develop an opinion about the source. Ants entering from outdoors can be discouraged by sealing as many cracks and gaps in exterior walls as possible.