Chilocorus nigritus (F.) surviving treatment with triazophos were used as parents and the offspring subjected for five to continued triazophos selection. A tendency to develop resistance against triazophos was indicated.
Phyto carinata sp. nov. is descriptionbed from South Africa and the males of P. stuckenbergi Crosskey and P. longirostris Crosskey are descriptionbed for the first time. It is argued that these three species constitute a monophyletic group within Phyto Robineau-Desvoidy. A revised key to Afrotropical species of Phyto is provided.
Two new genera of predaceous midges of the Tribe Ceratopogonini are descriptionbed from South Africa: Ankylohelea gen. nov., with type-species Ankylohelea montana sp. nov. and Capehelea gen. nov., with type-species Capehelea steli sp. nov.
Seventeen alphavirus isolates (16 Middelburg and 1 Sindbis) were obtained from 3957 Aedes Juppi mosquitoes collected at a single site on a farm at Tweespruit in the south-western Orange Free State Highveld. Collections were thought to be the first brood of the season and the appearance of Middelburg virus due to the presence of transovarially infected mosquitoes. This could indicate that Ae. juppi serves as a reservoir vector to carry this virus through dry inter-epizootic periods.
Four genera of Ochodaeidae occur in Africa, Ochodaeus Serville, Chaetocanthus Phinguey, Namibiotalpa gen. nov. and Synochodaeus Kolbe.Eight new species Ochodaeus, one of Chaetocanthus, one of Namibiotalpa and two of Synochodaeus are descriptionbed. Keys are provided to the genera and species and all species are descriptionbed and their distribution mapped.
Observations on the oviposition behaviour of the southern African robber fly Neolophonotus dichaetus Hull are descriptionbed. Females lay their eggs in a frothy secretion between the leaves of certain legumes. This is a behaviour not previously recorded in the family Asilidae. The egg-masses and first-instar larvae, which lack tubercles or pseudopods on the first abdominal segment, are descriptionbed and illustrated. Data on the distribution, seasonal incidence and adult behaviour of the species are presented.
In this study site selection for oviposition purposes, effects of rain on egg rafts, fecundity, seasonal occurrence and abundance of Culex quinquifasciatus in an urban site were studies over a period of three Seasons. Each Season represented a period between the date on which the first egg rafts were produced, till the date in early winter of the consecutive year on which the last egg rafts were laid. It was concluded that Cx. quinquifasciatus is an excellent r-strategist, probably to ensure survival during adverse environmental conditions in winter.
Three new species Hypacostemma Linnavuori viz. H. brevis, H. falcata and H. devia. H. uniformis (Distant) and H. viridissima Linnavuori are redescriptionbed and their rank as separate species established. A key to the genus is provided.
Culex pipiens Linnaeus from South Africa and England and Culex pipiens var. molestus Forskal from England were compared in respect of five quantitative morphological characters to assess their taxonomic status. Ranges of values for each of the characters in the 3 mosquito forms overlapped. A laboratory colony was established with Cx. pipiens from England and compared to Cx. pipiens from South Africa.
The moth Carposina autologo Meyrick was introduced from Australia to South Africa to reduce accumulated seed on the weed Hokea sericea Schrader. The previously devised methods of releasing the moth are reviewed, its level of establishment monitored at two sites, and reasons are given for the suspension of this programme in 1983.
Two new species of Buprestidae, Discoderoides pygmaeus (Agrilinae: Coroebini) and Ankareus natalensis (Mastogeniinae), are descriptionbed from north-eastern Natal. Both species are discussed in context to recent comments regarding generic identity.
Predation on the immature stages of the dung-breeding buffalo fly Haematobia thirouxi potans (Bezzi) by members of species from the families Staphylinidae, Histeridae and Hydrophilidae (Coleoptera) from the southern African dung fauna was examined in the laboratory. Field-collected adult beetles were tested individually in small chambers containing dung that had been infested with fly eggs.
A descriptionption of the anatomical and histological structure of the alimentary canal of Hodotermes mossambicus as studied by light microscopy is given. The surface structure of the intima as studied by the SEM is discussed. Differences in the alimentary canals of the castes studied are pointed out.
Neither newly flown alates nor young incipient colonies of the harvester termite Hodotermes mossambicus (Hagen) were able to reduce acetylene. The major and minor workers of established colonies were able to do so at a low rate. The larvae did not possess this ability. Much of the ethylene produced by intact colonies can be ascribed to acetylene reduction by the faeces which lose this ability on ageing or desiccation.