Cremastus Gravenhorst, 1829

Neocremastus Cushman, 1917: 509 Zaleptopygus Viereck, 1911: 294

Diagnosis (updated from Townes, 1971). Fore wing 2.5–9mm long; body slender; occipital carina mid-dorsally incomplete, the free upper ends down curved, ventrally joining oral carina near mandibular base; mandible of moderate length, usually subequal but sometimes one tooth slightly longer than other; maxillary and labial palpi of moderate length, with five and four segments respectively; scutellum weakly to moderately convex, often with a weak lateral carina; propodeal carination complete or nearly so; fore wing with marginal cell short, areolet open, rs-m opposite to basal to 2m-cuby 0.5x rs-m length, and Rs & M opposite or slightly basal to cu-a; hind wing with 1/Cu & cu-a usually intercepted near posterior 0.4, distal abscissa of Cu spectral to absent; hind femur simple; tergite 1 with long and shallow glymma, its lower edges separated and parallel, rarely almost touching; thyridium absent; epipleurum of tergite 2 narrow, separated by a crease and turned under; ovipositor sheath 1.4–3.8x longer than hind tibia; ovipositor tip straight, down-curved or weakly sinuate. Male: ocelli not enlarged; apex of gonosquama with a long ventral asymmetric lobe, lobe separated by a concave area from a dorsal tooth or short lobe near base.

Phylogeny. Monophyly of Cremastus as currently defined is debated with generic delimitation of Cremastus and Trathala unclear. The genus is mostly defined by the putative synapomorphy of the transformed male genitalia: females being mainly differentiated from Trathala by the mid-dorsal incompleteness of the occipital carina, a character state which, however, also occurs in some Trathala species.

Biology. The usual hosts are coleopteran stem borers or gall makers, but there are also records from lepidopteran larvae.

Species richness and distribution. This is a large genus of Holarctic distribution, with about 130 described species. Only two species are known in the Afrotropical region, of which one is restricted to Madagascar and the second is described here from South Africa. Morley (1926) erroneously reported two males of C. geminus Gravenhorst, 1829 from South Africa, which were later identified as Trathala sp. by Townes and Townes (1973). We also collected females of two other putatively new Cremastus in South Africa, but without associated males to confirm the genus affinity.

Genotype. Cremastus spectator Gravenhorst, 1829.