The Halictidae is the second largest family of Apoidea bees. Halictid species occur all over the world and are usually dark-colored and often metallic in appearance. Several species are all or partly green and a few are red; a number of them have yellow markings, especially the males, which commonly possess yellow faces, a pattern widespread among the various families of bees. They are commonly referred to as "sweat bees" (especially the smaller species), as they are often attracted to perspiration. They are likely to sting only if disturbed; the sting is minor.