156. Formica Agra ^HNS. B.M.

Worker. Length 5 1/2 -6 lines.-Elongate, slender; very variable in colour, some specimens with the head black, and the thorax and abdomen dark brown, the legs being paler; other examples have the head fuscous, the thorax and abdomen being of a reddish-brown, the latter with the apex darker. Head widest, narrowing behind the eyes into a slender neck; the antennae long and slender; the prothorax elongate, much narrowed anteriorly; the legs elongate and slender. Abdomen ovate; the scale of the peduncle incrassate and subconical; the apical margins of the segments of the abdomen pale testaceous.

Hab. Rio (Petropolis); Columbia. (Coll. Rev. H. Clark.)

This is one of those extraordinary forms which differ so widely from the generality of worker ants, that it might possibly constitute a new genus, or a distinct section; the male and female being unknown, it is retained in the genus Formica ^HNS; in form it is very like F. singularis ^HNS,