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The ant genus Polyrhachis F. Smith in the Ethiopian region (Hymenoptera: Formicidae)

1973; Natural History Museum; Volume: 28; Linguagem: Inglês

10.5962/bhl.part.11170

0524-6431

Barry Bolton,

Insect and Arachnid Ecology and Behavior

GENERIC DIAGNOSIS.Worker.Monomorphic, medium to large (4-4 to 14-1 mm) ants belonging to the formicine tribe Camponotini.Antennae 12 -segmented, the scapes inserted some distance behind the posterior clypeal margin (usually a distance greater than the basal width of the scape).Palp formula 6,4; mandibles usually with five, rarely with four teeth.Eyes well developed.Pronotum armed with a pair of spines, teeth or tubercles in all species of the Ethiopian region, the propodeum usually armed with two spines, teeth or tubercles, or a pair of ridges, rarely with only a single transverse ridge or completely unarmed.Promesonotal suture usually present (absent from khepra), the development of the metanotal groove variable.Mesoscutellum very rarely present.In the single species in which the mesoscutellum occurs on the dorsum of the alitrunk, it is not separated from the scutum by a deep impression.Margination of the alitrunk variable, often present and complete but showing all stages through to a fully immarginate condition.Petiole usually with four but occasionally with two or six spines or teeth of variable configuration.Gaster large, globose, the first tergite extensive, usually forming at least half of the dorsal surface.The anterior face of the first gastral tergite is often truncated or concave.Acidopore not borne upon a conical projection of the hypopygium, usually concealed by the pygidium when not in use.Female.As worker but with the alitrunk massively developed and with a corresponding reduction in armament and margination.The petiolar spines tend to be reduced and are usually smaller than those of the associated worker.Ocelli are present and wing venation is of the usual camponotine form.Male.Very poorly known, in most cases indistinguishable from the males of Camponotus.GENERIC AND SUBGENERIC SYNONYMY.Smith (1857) erected the genus Polyrhachis to include some twenty species and designated Formica bihamata Drury as the type-species.The following year Gerstaecker (1858) formed the monotypic genus Hoplomyrmus with the type-species schistaceus Gerstaecker for a large species from the Ethiopian region.These two type-species were recognised as being congeneric and Hoplomyrmus was later synonymised with Polyrhachis.