Before the advent of modern synthetic organic insecticides, entomologists had only a limited choice at their disposal. Available insecticides had to be used to best advantage by exploiting their mode of action superimposed on a detailed knowledge of the biology of the pest species. Depending on specific biological characteristics of the pest species such as feeding behaviour, whether they live in or on a commodity, mobility of the different developmental stadia, etc., the insecticide was selected on its mode of action, viz. its stomach toxicity, contact action, fumigant action, smothering ability, and so on.
Nine new species of Membracidae from the Congo, Uganda, the Central African Republic, South and South West Africa are descriptionbed here. They are from the collections of the Musï¿½e Royal de l'Afrique Centrale, Tervuren (M.R.A.C.), the South African Museum (Natural History), Cape Town (S.A.M.), and the National Collection of Insects of the Plant Protection Research Institute, Pretoria (N.C.I.). All measurements are in mm.
Chaetostricha miridiphaga spec. nov. (Hymenoptera: Chalcidoidea), reared from eggs of Lygidolon laevigatum Reut. (Hemiptera: Miridae), is descriptionbed and figured. Dr D. P. Annecke, Plant Protection Research Institute, Pretoria, submitted to me for determination a trichogrammatid reared from eggs of Lygidolon laevigatum Reut. (Hemiptera: Miridae). It represents an interesting new species of the genus Chaetostricha Walk. and is descriptionbed here.
The ten species of Dennyus that have been descriptionbed from swifts belonging to the genera Apus and Cypsiurus are dealt with. Reasons are given for considering five of them (Nitzschia minor Kellogg & Paine, 1914; Dennyus truncatiformis Mokhehle, 1951; D. africanus Bï¿½ttiker, 1954; D. maritimus Bï¿½ttiker, 1954; D. minutus Bï¿½ttiker, 1954) to be synonyms of D. hirundinis (Linnacus) sens. lat. A sixth species (D. clayae Nakagawa, 1959) is represented by insufficient material for any conclusions to be reached. The remaining four species (D. hirundinis (Linnaeus, 1761); D. cypsiurus Thompson, 1948; D. vonarxi Bï¿½ttiker, 1954; D. aequatorialis Ledger, 1968) are descriptionbed and illustrated; a key is provided for their identification. The relationships of certain host species are discussed in the light of their Dennyus parasites.
Eatonica crassi spec. nov. and Ephemera mooiana spec. nov. are descriptionbed and figured; their relationshiips to other ephemerids are discussed. During the course of a study to determine the phylogenetic relationships between genera of Ephemeridae, a number of specimens representative of the Ethiopian fauna were examined. Among the material borrowed, a new species of Ephemera from Natal was discovered, and several specimens from Africa in the collection of the University of Utah proved to be a new species of Eatonica. The two new species are descriptionbed here and their relationships to other ephemerids are discussed.
Population changes of Panonychus citri (McG.) were studied during 1966-67 at Addo, eastern Cape Province, in an orange orchard that had not been treated with insecticides or acaricides since 1961. The maximum numbers occurred between March and June and between August and September. Variations in numbers were related to fluctuations in temperature and relative humidity.
The presence of a volatile sex pheromone in the female bagworm was demonstrated by means of a bioassay based on the male copulatory response. The species is unusual in that the site of production of the pheromone is located anteriorly, as shown by bioassay and supported by histological evidence. The pheromone was partially purified by means of thin-layer and gas-liquid chromatography.
Two new bothriothoracine genera of Encyrtidae are descriptionbed, namely Macchiencyrtus for the type-species M. stigmosus spec. nov. and two other South African species, M. secus and M. tertius spp. nov., all of which are probably parasitic in scale insects; and Hesperencyrtus for the West African type-species Paraphaenodiscus lycoenephila Risbec, 1951, a parasite of the pupa of a lycaenid butterfly.
A new species of Plegadiphilus is descriptionbed from Geronticus eremita (Aves: Threskiornithidae). The male genitalia bear a resemblance to those of Eucolpocephalum, and this is taken as further evidence that the two genera evolved from a common ancestor. The six known species of Plegadiphilus are tentatively assigned to three species-groups on the basis of the head chaetotaxy and the structure of the male genitalia. Comments are made on the identity of Plegadiphilus mamillatus and on the nymphal abdominal tergal setae in Plegadiphilus.
The hymenopterous parasites of tsetse flies (Glossina) include three known species in the family Mutillidae (Buxton, 1955). All were originally descriptionbed by Turner (1915, 1916, 1920) and all were placed in the portmanteau genus Mutilla. In view of the possible importance of these parasites as control agents of tsetse, and because of recent investigations on parasitisation of Glossina species (e.g., Heaversedge, 1968, 1969a, 1969b), the species of Mutillidae involved should be assigned to their correct genera. Two of the species are included in the new genus Chrestomutilla (descriptionbed below) and the third is transferred to the genus Smicromyrme.
In a controlled-environment room programmed to simulate summer, autumn and winter conditions observed in the Eastern Cape, development of Panonychus citri (McGregor) was most rapid under summer conditions, the mean generation time being 31 days. Under autumn and winter conditions the mean generation time was increased to 50 and 70 days respectively. The greatest effect of the different conditions was on the incubation period of the egg.
In this study the identity of Diaspidiotus africanus is discussed, and the following species are found to be junior synonyms of it: Aspidiotus pectinatus Lindinger, Aspidiotus mashonae Hall, Aspidiotus (Diaspidiotus) mazoeensis Hall, and Clavaspis betrokensis Mamet. Clavaspis perplexus and Diaspidiotus yomae, both from South Africa, are descriptionbed as new, while Diaspidiotus ancylus (Putnam) and D. osborni (Newell & Cockerell) are recorded from this country for the first time, and redescriptionbed. A redescriptionption of Dynaspidiotus regius Brain is also presented.
The effects of temperature and photoperiod were investigated in the laboratory. Time of eclosion was not affected by the photoperiod to which larvipositing females were subjected, but was affected by temperature. Eclosion was limited to the range 18-32ï¿½ C and was stimulated by change in temperature. Even a small change caused a response, and the rate of eclosion appeared to be related to the rate of temperature change. In nature, normal diurnal temperature changes would therefore result in apparent rhythms of eclosion, the pattern being bimodal in summer when mid-day temperatures are above the upper limit and unimodal in winter.