Melophorus insularis

Identification
This species closely resembles Melophorus iridescens but the worker major is quite different in its more slender stature, smaller and differently shaped head, less emarginate clypeus, short.er frontal groove, coarser sculpture, striolate cheeks, shorter scapes and blunter petiolar scale. It differs from Melophorus curtus in its larger size, smaller head, longer scapes, less distinct clypeal emargination, more posteriorly placed eyes and in lacking pubescence on the thorax. It differs from Melophorus constans in its larger eyes, less emarginate clypeus, longer scapes, more pronounced mesoepinotal impression, thicker and less acute petiolar scale and metallic gaster. (Wheeler 1934)

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  insularis. Melophorus insularis Wheeler, W.M. 1934d: 151 (s.w.) AUSTRALIA.

Worker
minor Length 3.5 - 4.5 mm.

Head without mandibles scarcely broader than long, with straight, subparallel sides, sharp anterior corners and the posterior border and corners together broadly arcuate. Clypeus with the anterior border more projecting in the middle and even less distinctly sinuate. Antennae more slender than in the major, extending about half their length beyond the posterior border of the head. Eyes larger and slightly more convex. Thorax like that of the major, but the promesonotum less convex, the pronotum proportionally longer, the epinotum above straight and sloping, convex only where it rises from the mesoepinotal impression and at its posterior end. Petiole with lower, thicker scale than in the worker major.

Sculpture and pilosity very similar, but there are no erect hairs on the scapes and the appressed hair, or dilute pubescence on the tip is: shorter and sparser.

Black; gaster with metallic green reflections; mandibles, cheek, gula, antennae and legs castaneous; posterior borders of gastric segments yellowish.

major Length 5.5 mm.

Head moderately large, subrectangular, about one-fourth broader than long without the mandibles, with straight posterior border, broadly rounded posterior corners and straight, subparallel sides. Eyes rather large and convex, their longest diameter somewhat greater than twice the greatest diameter of the antennal scapes, situated behind the middle of the sides. Mandibles convex, not geniculate at the base, with oblique 5-toothed masticatory borders, the apical tooth long, a short but distinct diastema between the third and fourth and the fourth and fifth tooth, the last turned slightly backward. Clypeus convex and subcarinate in the middle, its anterior border produced and very feebly and narrowly sinuate in the middle. Frontal area very distinct, triangular; frontal groove short, reaching only halfway to the anterior ocellus. Antennal scapes extending fully one-fourth their length beyond the posterior border of the head; second and third funicular joints subequal, slightly more than twice as long as broad, distinctly shorter than the first joint. Thorax rather. long; pro- and mesonotum, especially the latter, very convex and rounded above, the promesonotal suture strong and impressed, the pronotum without the neck more than twice as broad as long; the mesonotum subcircular; mesoepinotal impression in profile short, acute and rather deep; epinotum small, much lower than the mesonotum, as broad as long, feebly convex, sloping, without distinct base and declivity. Petiole about twice as high as long, the scale distinctly inclined forward, moderately thick, with flat anterior and posterior surfaces, convexly bevelled above, the superior border entire, broadly arcuate, not sharp, the sides straight and converging ventrally. Gaster large, first segment subtruncate.

Moderately shining; mandibles coarsely, longitudinally rugose, with coarse, elongate punctures between the rugae. Head, thorax and legs finely and regularly reticulate; the meso- and metapleurae more coarsely; clypeus, cheeks and front finely and sharply longitudinally striate. Petiole and gaster smoother and more shining, the latter very finely, transversely shagreened and sparsely punctate; antennal scapes subopaque, coarsely reticulate, or granular.

Hairs yellowish, short, very sparse, erect on the head, pronotum and gaster, long on the clypeus and gula but not forming a psammophore; shorter, more numerous and appressed on the appendages, the scapes with a few short erect hairs and the gaster with sparse appressed hairs representing a coarse but very dilute pubescence.

Mandibles, head, thorax, petiole and appendages red; anterior border of pronotum, scapes, coxae, femora, epinotum and petiole darker, brown; gaster black, with pronounced metallic green reflections. In some specimens the infuscation is deeper and more extensive on the thorax, invading the mesonotum and occiput.

Type Material
Several specimens taken by Dr. Darlington and myself from a single nest under a stone near White Hill (X. 23. '31), and three taken by Mr. Glauert at City of York Bay (XII.13.'32).