Engramma denticulatum, Forel, 1922

Wheeler, W. M., 1922, The ants collected by the American Museum Congo Expedition., Bulletin of the American Museum of Natural History 45, pp. 39-269 : 204-205

Engramma denticulatum , new species

Text Figure 51

Worker.- Length 2.6 mm.

Head subhexagonal, a little longer than broad and slightly broader behind than in front, with the sides subangulate in the middle and the posterior border feebly concave. Eyes moderately large, near the middle of the sides. Mandibles rather small, convex, with three large apical and several small basal teeth. Clypeal notch small, semicircular, less than one-fifth as long as the anterior border, with sharp corners. Frontal area indistinct; frontal groove obsolete. Antennal scapes extending somewhat farther than their greatest diameter beyond the posterior corners of the head; first funicular joint as long as the two succeeding joints together; joints 2 to 7 about one and one-half times as long as broad, joints 8 to 10 slightly longer than broad. Thorax long, with very deep and broad mesoepinotal constriction so that it is dumb-bell-shaped, the pronotum and mesonotum convex and hemispherical above, the impression bearing the prominent mctathoracic spiracles, the epinotum high and convex like the promesonotum, with two blunt denticles and prominent spiracles. Petiole stout, through the distinct node-like thickening at its anterior end nearly half as high as long. Gaster shaped as in the other species of the genus, with the first segment overlying the petiole; anus terminal.

Shining; head and clypeus finely but distinctly longitudinally aciculate; mandibles smooth, with coarse, scattered punctures; pronotum finely and indistinctly punctate; meso- and epinotum opaque, densely and rather coarsely punctate; gaster finely reticulate.

Pilosity and pubescence very sparse, the latter distinct only on the appendages. Deep castaneous, nearly black; apical portions of mandibles, bases of scapes, terminal tarsal joints and petiole yellowish.

Described from two specimens taken by Lang and Chapin between Lukolela and Basoko on fire-wood. Two imperfectly preserved specimens were taken by Bequaert at Masaki, between Masisi and Walikale, from the caulinary swellings of a Cuviera (probably C. angolensis; Part IV).

This is a very strongly marked species on account of the peculiar shape of the thorax, the two denticles of the epinotum, and the peculiar sculpture of the head and thorax.