Myrmelachista donisthorpei

Distribution based on Regional Taxon Lists
Neotropical Region: Guyana.

Nomenclature

 *  donisthorpei. Myrmelachista (Decamera) donisthorpei Wheeler, W.M. 1934g: 204 (w.) GUYANA. Combination in M. (Hincksidris): Kempf, 1972a: 149.

Worker
Length about 1.3 mm.

Head subrectangular, convex dorsally, as broad as long and nearly as broad in front as behind, with feebly convex sides and posterior border. Eyes rather fiat, at the middle of the sides. Mandibles moderately convex, 5-toothed, the third and fifth tooth small. Clypeus broad, convex in the middle, anterior border transverse, nearly straight, without median denticle. Frontal area large, fiat, subtriangular, with indistinct posterior boundary. Antennae rather long; scapes reaching nearly to the posterior border of the head; funicular joints 2-6 small, slightly broader than long, except the second, which is as long as broad; two basal joints of club longer than broad, together shorter than the terminal joint. Thorax rather robust, of the usual hour-glass shape, the mesoepinotal constriction short but deep, both dorsally and laterally; promesonotum large, convex and hemispherical, considerably elevated above the epinotum; metanotum short, with prominent spiracles, without posterior suture; epinotum in profile with feebly convex, horizontal base, distinctly shorter than the straight and sloping declivity. Petiole stout, posteriorly pedunculate; scale strongly inclined forward, very thick, nodiform, as thick at the summit, which is rounded and entire, as at the base. Gaster of the usual shape. Legs long and slender, fore femora distinctly enlarged.

Smooth and shining, minutely and sparsely punctate; mandibles delicately reticulate-punctate.

Hairs rather abundant, yellow, of uneven length, bristly, long on the body, shorter on the appendages, appressed on the femora, suberect and conspicuous on the tibire, especially on the tarsi, funiculi and anterior surfaces of the scapes.

Pale yellow; mandibles reddish; vertex and middle of occiput with a large pale brown spot; gaster piceous or blackish.

Type Material
A single specimen, taken by the Oxford University Expedition (1929) on Morabelli Creek, Essequibo River, British Guiana and sent me for identification by Mr. Horace Donisthorpe. It is deposited in the British Museum together with a dealated female from the same locality and apparently belonging to the same species. This specimen unfortunately lacks the anterior half of the head. It is deep castaneous, with black gaster and yellow legs. Both body and legs are rather densely clothed with erect or suberect, coarse, yellow hairs, of uneven length. Petiolar scale or node broad and very thick, with transverse, somewhat sinuate superior border.