Myrmelachista flavida

Identification
M. flavida is closely related to Myrmelachista nodigera, Myrmelachista bambusarum and Myrmelachista bruchi, but is, I believe, quite distinct. (Wheeler 1934)

Distribution based on Regional Taxon Lists
Neotropical Region: Guyana.

Nomenclature

 *  flavida. Myrmelachista (Decamera) flavida Wheeler, W.M. 1934g: 205 (w.) GUYANA. Combination in M. (Hincksidris): Kempf, 1972a: 149.

Worker
Length 1.3-1.5 mm.

Head flattened, subrectangular, about one sixth longer than broad, slightly narrower in front than behind, with nearly straight sides and slightly sinuate posterior border. Eyes flat, slightly in front of the middle of the sides. Mandibles moderately convex, somewhat geniculate at the base, 5-toothed, the third and fifth tooth minute. Clypeus convex in the middle, its anterior border sinuate on each side, broadly rounded in the middle, somewhat projecting and armed with a distinct denticle. Frontal area distinct, flat, triangular. Antennal scapes curved at the base, extending to about half the distance between their insertions and the posterior corners of the head; funicular joints 2-6 small, subequal, much broader than long; two basal joints of club slightly broader than long, together much shorter than the swollen terminal joint. Thorax slender, hour-glass shaped; pro- and mesonotum together forming an ovoidal mass, convex dorsally and laterally; mesoepinotal constriction deep and rather long; metanotal spiracles prominent, posterior metanotal suture obsolete. Epinotum seen from above ovoidal but smaller than the promesonotum; base in profile nearly straight, horizontal, decidedly longer than the somewhat concave, sloping declivity. Petiole as long as high, slightly pedunculate posteriorly, the scale small, thick, nodiform, inclined forward, its upper border rounded, seen from behind straight and entire. Gaster of the usual shape. Legs moderately long, fore femora slightly thickened.

Smooth and shining; mandibles delicately reticulate-punctate at their tips; thoracic constriction and metanotum subopaque, reticulately and on the sides longitudinally rugulose.

Pilosity delicate, yellowish, short and very meager; only a few scattered erect hairs on the clypeus, upper surface of the head, thorax and gaster. Pubescence very dilute, appressed, scarcely visible, except on the antennre, tibire and posterior surface of the head.

Yellow; gaster and legs slightly paler than the head and thorax; borders and teeth of mandibles, anterior margin of clypeus and the frontal carinae reddish.

Type Material
Described from six specimens which I collected at Kartabo, British Guiana, nesting in dead stems of a low Rubiaceous weed, Borreria verticillata L.