Ocymyrmex hirsutus Forel

Bolton, B., 1981, A revision of six minor genera of Myrmicinae (Hymenoptera: Formicidae) in the Ethiopian zoogeographical region., Bulletin of the British Museum (Natural History) Entomology 43, pp. 245-307 : 271

Ocymyrmex hirsutus Forel

Ocymyrmex weitzeckeri subsp, hirsutus Forel , 1910 b: 13. Syntype workers, South West Africa: Severelela and Kooa (L. Schultze) (MHN, Geneva) [examined]. Ocymyrmex hirsutus Forel ; Santschi, 1913: 431. [Raised to species.]

Worker. TL 6.9 - 7.8, HL 1.54 - 1.82, HW 1.48 - 1.74, CI 93 - 97, SL 1.40 - 1.62, SI 90 - 95, PW 0.96 - 1.14 AL 2.04 - 2.36 (7 measured).

Anterior clypeal margin with a conspicuous semicircular median impression which is flanked by a pair of teeth or denticles. Occipital margin in full-face view slightly indented or flattened to feebly concave medially, not evenly transversely convex. Maximum diameter of eye 0.32 - 0.38, about 0.21 - 0.23 x HW. Alitrunk in profile with promesonotum evenly convex, sloping behind to the propodeum. Dorsum of propodeum sloping very weakly, rounding broadly and evenly into the declivity. Metapleural lobes short and bluntly triangular. Petiole in profile with a small, low, evenly rounded node, the peduncle without a ventral process but broadly and very shallowly sinuate in some workers. Petiole node in dorsal view varying from as broad as long to distinctly broader than long. Postpetiole dorsally longer than broad. Base of first gastral tergite constricted and forming a narrow neck behind the postpetiole. Rugulose sculpture on dorsum of head fine, irregular and very densely packed, with fine punctulate to granular ground-sculpture between the narrow rugulae. To the level of the posterior margins of the eyes the rugulae are mostly or entirely longitudinal to arched-longitudinal, the pattern varying from specimen to specimen. Behind this level the rugulae are transverse or arched-transverse, tightly packed and narrowly vermiculate. In some the rugulae are so fine and close together, and so narrowly vermiculate, that the occipital sculpture appears as a disorganised mass of narrow irregular wiggly transverse lines. Dorsal alitrunk and declivity of propodeum transversely rugose except between the mesothoracic spiracles where the sculpture is longitudinal. Extent of this longitudinally sculptured area variable, the further forward the rugae extend the more strongly arched is the transverse sculpture of the pronotum. In some the pronotal dorsum is mostly arched-longitudinally rugose. Sides of alitrunk rugose, the sides of the pronotum finer and less densely so than the pleurae. Petiole with a few transverse rugae ventrally and the peduncle also with a few dorsally, but otherwise the segment only superficially sculptured. Postpetiole unsculptured. All dorsal surfaces of head and body except first gastral tergite densely clothed in acute hairs of varying length, very numerous on the dorsal alitrunk. On the sides of the pronotum the hairs are directed forwards; on the pleurae they point backwards and downwards. First gastral tergite with sparse short hairs on the surface and with a denser transverse apical row. Colour reddish, the gaster the same colour as the alitrunk or lighter.

Apart from its dense pilosity hirsutus can quickly be recognized by the distinctive sculpture of the head, described above. Transverse sculpture on the area of the head behind the eyes is also found in robecchii and in females of the various species of Ocymyrmex , but in all of these the sculpture consists of regular transverse costulae, not narrowly vermiculate rugulae.