Sp. 11. Pseudomyrma cephalica, n. s.

Female.-Length 3 lines. Pale yellow testaceous, very smooth and shining; the head thrice as long as broad, the sides parallel, the eyes elongate-ovate; the mandibles black at their tips; the posterior margin of the vertex slightly emarginate. Thorax narrower than tlie head, elongate, rounded in front and behind; a minute black spot at the insertion of the wings, which are hyaline and beautifully iridescent; the femora broad and compressed. Abdomen petiolate, the petiole of nearly equal width throughout, or very slightly widest towards the apex; the second segment sub-globose; the base of the third segment fuscous, the two apical ones black, or fuscous.

Worker.-Length lines. Rufo-testaceous; the head and thorax palest; the entire insect is covered with a delicate silky pile, most observable on the abdomen; the head oblong, the eyes large, occupying a large portion of the sides of the head; the petiole of the abdomen narrowest at the base; the first segment sub-globose, widest at the apex, this and the following segments slightly fuscous, and sprinkled with a few glittering hairs.

This sex is very like the P. oculata, of which a figure is given, but the head is proportionably rather narrower; the prothorax is oval, not widest in front; the petiole is rather shorter, and not so slender at the base.

Male.-Length 2\ lines. Testaceous; the antennae and legs pale testaceous; the head scarcely longer than broad; the eyes large, oval and placed at the sides of the head anteriorly; the ocelli large and glassy bright; the sides of the head rounded behind the eyes; the vertex emarginate. Thorax, the scutellum prominent; the wings hyaline, and beautifully iridescent, the nervures and stigma pale testaceous; the abdomen of the same form as that of the worker; the insect thinly covered with fine short silky pubescence.

Hab. Brazil (Villa Nova, on the Amazons).