The mosquito and Culicoides faunas were surveyed at Bethulie and
Luckhoff in the arid Karoo region, southern Orange Free State, to
determine which species occurred, their relative prevalence and the
effects of rainfall. The feeding preferences of these insects were also
investigated by means of baited catches. Twenty-three mosquito
species and 16 Culicoides species were collected. The commonest
mosquito species, with their feeding preferences, if known, were as follows: Culex (Culex) univittatus Theo and Culex (Culex) pipiens Linnaeus, which are strongly ornithophilic and poorly anthropophilic; Culex (Culex) theileriTheo, which feeds on sheep and man avidly but is only moderately ornithophilic; Aedes (Neomelaniconion) luridus McIntosh, Aedes (Neomelaniconion) lineatopennis (Ludlow), Aedes (Ochlerotatus) caballus (Theo) and Aedes (Ochlerotatus) juppi
McIntosh, all of which feed on sheep and man readily and which can aestivate as eggs for up to 20 months but only appear in numbers after rain; Anopheles (Cellia) listeri De Meillon, Anopheles (Cellia) squamosus Theo, Culex (Culex) quinquefasciatus Say and Culiseta (Allotheobaldia) longiareolata (Macquart). By far the commonest Culicoides at both localities was Culicoides pycnostictus Ingram & Macfie, which is strongly ornithophilic and also feeds on sheep. The following 5 species were also prevalent: Culicoides similis Carter,Ingram & Macfie, Culicoides spec. nov. 1., Culicoides schultzei (Enderlein), Culicoides ondersteportensis Fiedler and Culicoides nivosus De Meillon. The last species is strongly ornithophilic.