11. Formica irritans ^HNS.

F. capite abdomineque nigro-fuscis; antennis, thorace, abdomine, squamula pedibusque ferrugineis.

Worker. Length 6 lines. Elongate and slender; head ovate; dark fuscous; the apex of the scape and the flagellum ferruginous; the clypeus and mandibles dark rufo-piceous. The thorax, scale of the abdomen and the legs, ferruginous; the thorax elongate, compressed, with the prothorax very slightly dilated at the sides. The scale of the abdomen incrassate, rounded anteriorly and truncate behind. Abdomen ovate, nigro-fuscous; the entire insect sprinkled with erect pale hairs.

Worker minor. Length 3 lines. Only differs in having the antennae entirely pale ferruginous and the anterior legs stouter.

Hab. Malacca; Borneo (Sarawak).

This is probably the worker of F. diligens ^HNS.