Tapinoma sessile (Say), the odorous house ant, is a widely distributed native species found throughout the United States, in Canada, and Mexico. The common name of this insect is derived from a peculiar coconut-like odor produced in the anal glands. A large population of these ants live in western Washington, between Vancouver, British Columbia and Portland, Oregon. Odorous house ants are less common in the semidesert areas of the Pacific Northwest.
This publication explains how to identify and control these pests.