151. Formica solitaria ^HNS. Pl. XIII. figs. 4, 5.

Worker. Length 4 1/4 lines.-Opake-black, with eight or nine of the apical joints of the antennae of a palish yellow; the mandibles and claws of the tarsi rufo-piceous. Head very large, wider than the thorax or abdomen; eyes occupying the whole of the sides of the head, very convex and prominent; the clypeus very large, much produced and truncate at the apex, with a central longitudinal carina, and covered with a thin grey pile; mandibles large, stout, shining, and having their inner margin finely serrated; the head emarginate behind; the ocelli prominent on the vertex. Thorax elongate, narrow and compressed behind; the divisions of the thorax not very strongly marked; legs elongate and slender; the tibiae with a few fine scattered spines or hairs. Abdomen ovate, with a few pale hairs at the apex; the scale of the petiole incrassate, and, viewed sideways, wedge-shaped.

Female . Length 5 lines.-Very closely resembles the worker, differing only in the form of the thorax, which is of a more ovate form, as in the majority of species, and in having wings, the neuration of which is the same as in F. ligniperda ^HNS; the antennae; are elongate and slender, as in the worker.

Hab. Brazil (Ega).

This is a very remarkable insect; for, independent of the enormously developed eyes and produced clypeus, the palpi are elongated to half the length of the thorax, the maxillary are six-, and the labial four-jointed. Mr. Bates says, " This curious solitary ant is never seen by more than one at a time, prowling about fallen leaves, &c. in the forest; I have never seen its Formicarium, and, from its solitary habits, have no clue to guide me in looking for it."