Mandibles each with 4 teeth. Eyes each with 10 or more facets. Paired longitudinal carinae of clypeus obscure. Metanotal groove distinct. Ventral outline of petiole roundly convex.
Body surfaces smooth and shining, without sculpture.
The species is found in open land, ranging to woodland margins. It nests under stones or in plant cavities, such as small bamboo stems. M. intrudens is one of the most common ant species of southwestern Japan. Editor of the descriptions Original text by Kazuo Ogata and Mamoru Terayama. English translation by Kazuo Ogata, edited by Robert W. Taylor.