Acanthoponera occidentalis, Clark, 1926

Clark, J., 1926, Australian Formicidae., Journal of the Royal Society of Western Australia 12, pp. 43-52 : 47-48

Acanthoponera occidentalis n. ßp. (Pl. VI. 3).

Worker: Length,3.5-4mm.

Head, thorax and node castaneous, abdomen with a yellow tinge; mandibles, antennae and legs testaceous. Hairs yellow, long, slender and erect, abundant on the apical segments of the gaster, longer and more bristle-like on the elypeus. Pubescence yellow, long and adpressed on the gaster, shorter and more abundant on the antennae and legs.

Head and thorax opaque, gaster shilling. Head finely and longitudinally, rugose on the middle, finer and more punctate on the frontal areas and ou the sides. Mandibles shining, with largo,

scattered, piligerous punctures. Thorax densely and coarsely punctate, becoming almost rugose on the epinotum. Node eoarsely punctate. Gaster densely covered with wide, shallow punctures. Head longer than broad, as broad in front as behind, the occipital border concave, the angles rounded sides feebly eonvex. frontal carinae rather flat, overhanging the antennal insertions in front, extending back to the eyes, and continued further as feeble carinae; there is a faint carinae in the middle, between the frontal carinae, extending from the front edge of the clypeus to the occipital border; in some examples the carinae is scarcely to be distinguished from the rugae of the head. Clypeus broadly rounded in front, convex above. Eyes small, flattened, plaeed behind the middle of the aides. No traces of ocelli. Mandibles triangular, the external border eonvex, the terminal border armed with five long sharp teeth. Antennae short and robust, the scapes extending back slightly beyond the posterior margin of the eyes, they are gradually thickened to the apex; first joint of the funiculus about twice as long as broad, the second a little longer than the third, but broader than long, third to tenth broader than long, the apical joint about twiee as long as broad, and as long as the four preceding joints together. Thorax fully one and one half times as long as broad, broadest through the pronotum,, which is almost twice as broad as the epinotum at the top of the deelivity; pro-mesonotal suture sharply impressed; the suture between the mesonotum and the epinotum feebly indicated. The anterior and lateral borders of the pronotum convex, the anterior angles sharp, the posterior border of the epinotum concave, the angles produced as tooth-like projections; in profile the thorax is rounded and eonvex above, the epinotal deelivity abrupt, feebly margined above and on the sides. Node twice as broad as long, broadest just behind the middle, almost oval, but the posterior border not so strongly eonvex as the anterior; in profile it is more than twice as high as long, the anterior face sloping at a slight angle, the top edge rounded, the posterior face straight, the ventral surface with a moderately long sharp tooth-like projection almost directly under the anterior face; this tooth has a broad translucent lamella attached to its anterior edge, the lamella is as long as it is broad. First segment of the gaster broader than long, broader behind than m front, the anterior border straight, the angles rounded, the sides eonvex; in profile it is bluntly produced in front below. A slight constriction between the first and second segment. The second segment is as long as the first, it is broader in front than behind. The apical segments short, hidden by the second. Sting long and stout. Legs short and stout.

Hab.: Western Australia, National Park (J. Clark). Described from a small colony found under a stone.

This ant feigns death on being disturbed, or when the stone is removed from above the nest. This is the first example of the genus to be found in Western Australia. The other Australian species, A. imbellis Forel , was described from Queensland, but also oecurs in South Australia. I have lately received examples which were collected at Ferntree Gully, Victoria. The Variety hilaris Forel , was described also from Queensland.