Polyrhachis (Myrma) bequaerti, Wheeler, W. M., 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: 267-269

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Polyrhachis (Myrma) bequaerti

new species

Polyrhachis (Myrma) bequaerti  HNS  , new species

Text Figure 76


Length 4 to 4.5 mm.

Head, without the mandibles, scarcely longer than broad, broader behind than in front, with feebly convex posterior border and nearly straight, anteriorly converging sides, in profile nearly as high as long. Eyes moderately large and convex, broadly elliptical, their anterior orbits at the median transverse diameter of the head. Mandibles feebly convex, with five acute, subequal teeth. Clypeus convex, carinate, especially behind, the anterior border evenly rounded, entire. Frontal area very indistinct; frontal carinae very long and rather far apart, feebly sinuate, subparallel behind. Antenna; stout, the scapes only slightly enlarged and scarcely deflected at their tips, extending about one third their length beyond the posterior border of the head. Thorax short, as high as long, the dorsal surface strongly carinate laterally, the border deeply notched at the pronounced premesonotal and mesoepinotal sutures, especially at the latter. Pronotum very broad, without the neck nearly twice as broad as long, decidedly broader in front than behind, at the anterior angles with rather large, acute, triangular spines, which are flattened, diverging, and fully as long as broad at their bases. The surface of the pronotum is feebly convex. Mesonotum short and rather flat, more than twice as broad as long, narrower behind than in front, where it is almost as broad as the posterior border of the pronotum; its sides straight, but rounded at the corners. Epinotum extremely short, abruptly sloping, the base and declivity being in the same plane, the former strongly convex in front just behind the mesoepinotal suture, or fissure, which is much more deeply impressed than the premesonotal suture. The posterior corners of the base bear acute, slender, erect, recurved spines, which are fully twice as long as the diameter of their insertions. The surface of the base is bluntly and longitudinally carinate in the middle, the declivity feebly concave. Seen from behind, the base is distinctly broader than long, a little broader behind than in front, with convex, arcuate sides; the declivity, however, has concave and more feebly marginate lateral borders. Petiole thick, very convex anteriorly and posteriorly, especially anteriorly, as broad as high, its blunt upper border with four long, slender, acute, equidistant spines, the outer pair distinctly longer than the inner and all directed upward and somewhat, backward, with their tips somewhat more, strongly curved than their bases. Gaster subglobular, very slightly broader than long, very convex above, the first segment concave anteriorly for the accommodation of the convex posterior surface of the petiole. T.egs rather stout, tibiae distinctly constricted at the base.

Shining; mandibles smooth, with rather coarse scattered punctures; clypeus, cheeks, and anterior portion of front very smooth and shining; remainder of head regularly and rather finely longitudinally rugose, with punctate interrugal spaces. Pronotum and mesonotum above sharply and regularly longitudinally rugose, the rugae on the former coarser than on the head, on the latter radiating backward from a point in the middle of the anterior border. Base of epinotum with very regular transverse rugae, which are even sharper than those on the pronotum, giving the surface the appearance of a washboard. Lower pleunc finely punctate-rugulose, passing above into parallel ruga;, which are longitudinal on the sides of the pro- and mesonotum and nearly perpendicular on the epinotum. Epinotal declivity rugulosepunctatc, the rugules in the middle distinctly transverse. Anterior and posterior surfaces of petiole with similar sculpture, but the rugules somewhat less clearly transverse. Gaster smooth and shining, very finely and regularly reticulate. Legs finely and transversely shagreened.

Hairs whitish, delicate, erect, sparse, conspicuous only on the thoracic dorsum, tip of gaster, venter, and dorsal surface of head. Pubescence pale, short, fine, and appressed; rather dilute, longer, and sparser on the gaster; denser on the appendages.

Black; mandibles, funiculi, tibiae, and insertions and tips of scapes castaneous: palpi somewhat paler; femora and tarsi a little darker.

Described from fifteen specimens collected by Dr. Bequaert in the virgin forest at Utiasiki, between Lubutu and Kirundu. They were taken, together with their larvae and pupae, from a nest consisting of two leaves united by a soft tissue composed of fibrous, gnawed vegetable particles and silk.

This exquisite ant clearly belongs to the group comprising fissa Mayr  HNS  and monista Santschi  HNS  , but is quite distinct from any of the described species.