A synoptic view is given of the data amassed by WHO, with technical assistance from the Imperial College of Science and Technology, on the origins of blood-meals in Anopheles samples collected from 1971 to 1978. Attention is focused on the proportion of each sample found to contain human blood and on the problems of interpreting from this the human blood index or degree of biting-contact with man exhibited by vector populations. The difficulties of overcoming bias in sampling, which are formidable in unsprayed areas, are further compounded where the dwellings are treated with a slow-acting residual insecticide which knocks down many engorged mosquitoes before they can be collected from their daytime resting places. There is evidence to suggest that the host-selection patterns of those vectors which are ‘opportunistic’ feeders may be heavily influenced, even from village to village or from month to month, by the changing availability of alternative hosts, particularly cattle. This suggests in turn that the possibilities of manipulating the degree of mosquito-man contact by encouraging deflection to animals (zooprophylaxis) or by measures to afford a degree of personal protection should not be under-estimated by malaria strategists. It may sometimes be found less difficult to reduce the vector’s human blood index than it is to measure it, but in view of the epidemiological importance of this parameter, suggestions are put forward for improving entomological field practice in this area. They include a quantitative survey of the biotopes available to the mosquito population as diurnal shelters, a longitudinal survey of the densities of blood-fed females per biotope, and a survey of the numbers and the respective distribution of people and domestic animals available as hosts. The work-load entailed by such a thorough form of investigation, to be repeated where necessary at different seasons of the year, underlines the necessity to concentrate efforts on a small number of localities, carefully chosen for the malaria situations they represent and the vector populations they support. A large-scale blood-meal sampling programme, confined to these selected localities, is most likely in our estimation to yield information of value for controlling malaria vectors.

Energy values for Glossina morsitans morsitans Westw. and for the vertebrate blood which constitutes its food were determined. On this basis, energy budgets for the hunger cycle were drawn up over a range of temperatures. The results indicate that daily flight duration for females is limited to a few minutes, while for males it averages about 15 min in the hot season and more than twice as long in the cold season.

Examples of the persistence of adult infestations of Chortoicetes terminifera (Wlk.) in Australia were contrasted with ones where mass displacement took place. Migration occurred if sufficient rain had fallen at the nymphal stage to produce green pasture; persistence was associated with drought.

The demographic performance of a laboratory strain of Phthorimaea operculella (Zell.) was characterised by measurements of seven parameters under standard breeding conditions at six constant temperatures. The parameters were fertility, larval survival, sex ratio, weight of females, fecundity, development time and adult life-span. This information provides reference values which would be useful in experiments designed to determine the demographic effects of treatments, to identify strains and genetic populations of the species, and eventually to detect evolutionary changes in the specific properties of forms under study. The results of this investigation could be used in constructing simulation models of the species’ life system.

The dynamics of Bemisia tabaci (Gennadius) were followed during two years in treated and untreated cotton fields in three locations in Israel. Two parasite species, Encarsia lutea (Masi) and Eretmocerus mundus Merc., were the only important natural enemies, but percentage parasitism did not rise with increase in the host population. The whiteflies reached peak populations at the end of the summer. Their distribution upon the plants was not uniform, rather, they tended to concentrate on a few leaves. The leaf bearing the maximal population was the sixth or seventh until mid-July. From then on, its location was variable according to the growth pattern of the foliage. Insecticide treatments, in particular with aldicarb, resulted in depression of both whitefly and parasite populations, but neither was exterminated.

In a field study in eastern Tanzania, the behaviour of 4167 males and females of Glossina morsitans morsitans Westw. from a colony fed on equine blood through artificial membranes (Seibersdorf flies) was compared to that of 4065 flies from a colony fed on goats or rabbits (Tanga flies). All flies had been treated with 11·8 krad γ-irradiation, a sterilising does, in the late puparial stage in a saturated nitrogen atmosphere. Recapture rates were 5·66% for Seibersdorf and 4·50% for Tanga flies. Only 57% as many Tanga females were recaptured as compared to Seibersdorf females, but the Tanga females had a higher insemination rate. The age-distribution and dispersal of the recaptured flies of the males of both groups and of the females were similar. Laboratory studies showed that although there were no marked differences in fat reserves between males of the Tanga and the Seibersdorf strains, the Seibersdorf females had significantly more fat than the Tanga females.

The number of tsetse visiting a black cylindrical model (designed to look like a small host animal) in the Zambesi Valley, Zimbabwe, was estimated by catching them on an expanse of electric netting placed next to the model. The number which alighted was found by electrocuting the flies on the surface of the model on other occasions when the netting was absent. About half the Glossina morsitans morsitans Westw. visiting a stationary small model (a black drum 57 cm long and 37 cm in diametter) in the absence of ox odour alighted on it, but virtually none of the G. pallidipes Aust. alighted. When the linear dimensions of the standard model were increased threefold, about 1·5 times as many tsetse visited its close vicinity. Of these, nearly all the G. morsitans and about one-third of the G. pallidipes alighted on the model. Four to seven times as many tsetse visited the models when the odour of one ox was dispensed near them. When odour was present, about 1·5 times as many tsetse visited the large model as visited the small one. Some 55–85% of G. morsitans visiting the small model in the presence of ox odour alighted, but only about 30% of the male and 20% of the female G. pallidipes alighted. The latter percentages increased to 53 and 62 when the large model was used. A smaller percentage of G. morsitans females landed on the large model in the presence of ox odour than in its absence. With mobile models, significantly more tsetse were taken if electric nets were appended fore and aft of the model. In the absence of electric nets, 2–30 times as many tsetse landed on the large model as on the small one, the effect being greater for female G. morsitans than for males and much greater for G. pallidipes than for G. morsitans. The percentage of visiting flies of both sexes and species that landed was greater when the large model was used.

The genus Sosylus includes important natural predators and parasites of ambrosia beetles (Platypodidae). Nine species of Sosylus are recorded from New Guinea (Papua New Guinea and Irian Jaya in Indonesia), and a key is provided for their identification. Five of the species, S. giluwe sp. n., S. hyweli sp. n., S. minusculus sp. n., S. morobensis sp. n. and S. reflexus sp. n., are described as new and one, S. erosus (Pasc.), is recognised as an extension to the known range of an existing species. New information is presented concerning the distribution and sexual dimorphism of the previously described species, and lectotypes are designated where necessary and feasible.

A description is given of some of the developmental stages of Sosylus vicinus (Grouv.), S. silius Hinton and S. reflexus Pope from Papua New Guinea. At least three instars are recognised in all species, and the first or primary instar is of the triungulin type. A triungulin is also reported as the primary instar of another colydiid, Asosylus rhysodoides (Pasc.). This is the first time triungulins have been found in the coleopterous family Colydiidae. Differences in the triungulin of the three species of Sosylus are recognised, based on the form and arrangement of segmental spines. The structure of the different instars with regard to their habits on the host is discussed, and a brief comparison is made with larvae of Meloidae and Rhipiphoridae, the only two other families of Coleoptera with triungulin first-instar larvae.

The liquid excrement of many Homoptera, which often accumulates as honeydew, can be harmful to the insects that produce it. Disposal of excrement to avoid or reduce its harmful effect is therefore important. The methods of disposing of excrement in Coccidae are described. These insects have an anal apparatus for propulsion of excrement away from the body. The musculature of the rectum is not involved in this act. Attendance by ants modifies excretory behaviour in Coccidae, much as it does in Aphididae.

Andaspis dasi Williams, which was described from India, is made a synonym of A. numerata Brimblecombe, which was described from Australia. The species is now known from several localities and host-plants in the Pacific area and is often found on tea. A short account is given of its association with the fungus Septobasidium in Papua New Guinea.

Observations on the taxonomy, distribution and host-plants of scale insects of several taxa in the Middle East are reported. A lectotype is designated for Bodenheimera rachelae (Bodenh.). Coccus capparidis (Green) is recorded for the first time from Israel and the Mediterranean region. C. arens Hodgson is a new synonym of C. capparidis. C. pseudo-magnoliarum (Kuw.) is recorded from Israel and France. The genus Paralecanopsis is regarded as a subjective synonym of Lecanopsis. Archaspis is synonymised with Quadraspidiotus and Archaspis ephedrae Bodenh. with Quadraspidiotus cecconii (Leonardi). The identity of Diaspis capparidis Bodenh. is established, the species is transferred to Rungaspis, and R. trabuti Balachowsky synonymised with it. R. macrolobis Kaussari is redescribed and a lectoype designated; it is recorded from Israel. A key is given to the three species of Rungaspis, and Sinaidiaspis is synonymised with this. Pseudococcus lindingeri Bodenh. is transferred to Planococcus, and Planococcus variabilis (Hall) synonymised with it. Trionymus internodii (Hall) is recorded for the first time from pineapple and from Israel.

A pyralid moth belonging to the tribe Anerastiini, reared from larvae feeding in the rhizomes of Johnson grass (Sorghum halepense) in Pakistan, is described from the male and female and named Patna rhizolineata sp. n. It is differentiated from the closely related Afrotropical species P. venatella Hmps. As a result of the comparative study of type material, P. brunneicostella Hmps., Critonia sarcoida Hmps. and P. aulacodes Meyr. were found to be conspecific with P. venatella and are placed as junior synonyms of it.

A gall midge that attacks citrus flower buds in south-western Japan is redescribed under the name Contarinia okadai (Miyoshi) comb. n. and is compared with C. citri Barnes, which was originally described from cultivated citrus in Mauritius. C. okadai, for which a neotype is designated, is distinguished from C. citri by morphological characters of the adult males and females and of the larvae. The known host-plants, biology and distribution of C. okadai are recorded, and new Japanese and English names for the species are proposed. The status of records of C. citri from Sicily, Cyprus, Israel, India, China and Hong Kong is discussed, and the need for further taxonomic research is stressed.

Orius amnesius sp. n., a predator of Megalurothrips sjostedti (Tryb.) infesting cowpea, is described from the male and female from Nigeria. A sympatric species, Orius albidipennis (Reut.) was also attacking the pest. Wollastoniella gatti sp. n., a predator of tetranychid mites on ornamental species of Solanum, is also described from the male and immature examples from Kenya. O. amnesius resembles O. albidipennis and several other economically important and widely distributed species of Orius found in Africa, Asia and the Pacific.

Some eggs of Ephestia cautella (Wlk.) and E. kuehniella Zell. hatched after exposure to near 100% atmospheres of nitrogen (N2) or carbon dioxide (CO2) for up to 5 days at 15°C, 3 days at 20°C and 1 day at 25°C. The most tolerant age at the start of treatment at 25°C in E. cautella was 7–24 h after oviposition for CO2 and 7–30 h for N2. Generally, hatch was lower in CO2 than in N2 whatever the exposure, and lower for E. kuehniella than for E. cautella. Considerably more eggs of E. cautella aged 30 and 42 h hatched after exposure to N2 than to CO2, showing a toxic effect of CO2 in the absence of oxygen. Eggs of both species treated with either CO2 or N2 hatched 1–2 days later than controls, regardless of age or percentage survival.

The numbers of Glossina pallidipes Aust. and G. morsitans morsitans Westw. flying in and out of a large clearing in Zimbabwe were estimated from catches on unbaited electrified nets placed on the perimeter of the clearing. By estimating the numbers of flies that would encounter visual and olfactory attractants in the middle of the clearing, and from measurements of the numbers caught responding and estimates of the efficiency with which responding flies were caught, it was calculated that 80–100% of flying tsetse responded to stimuli they encountered. The importance of flight as a means of encountering host stimuli in woodland and open areas, and with mobile and stationary baits, is discussed.

Among collections from natural microhabitats in coastal forests in Kenya, larvae of Eretmapodites quinquevittatusTheo. and E. silvestris conchobius Edw. were recovered almost exclusively from water-filled snail shells, while those of E. subsimplicipes Edw. were found in tree holes, snail shells, leaf pools, cavities in fungi and most often in fruit husks. E. quinquevittatus oviposited in shells of Achatina fulica set as traps during periods when E. s. conchobius was not abundant, thereby reducing niche overlap of these two species in this microhabitat. The eggs of all three species were moderately drought-resistant. In the laboratory, larvae of E. subsimplicipes preyed upon larvae of Aedes aegypti (L.) but pupated sooner when offered particulate food instead. E. quinquevittatus failed to complete development on a diet consisting only of prey larvae. Mating and oviposition of all three species was achieved in the laboratory, and blood-feeding was not a prerequisite for insemination of E. subsimplicipes.

Nocturnally active mosquitoes are attracted visually to large (1·5 × 2·4 m) unpainted plywood suction traps. Such traps, which discharge air horizontally in one direction only, were placed in an open field in Florida in various patterns to study the flight behaviour of mosquitoes. When four traps were placed 15 m apart in a column, the two end traps captured 83 or 53% more mosquitoes than the two inner traps, depending upon whether the air discharged from the traps was perpendicular to, or in line with, the trap column. When the traps were spaced 30 m apart, the end traps captured only 13% more than the inner traps, indicating that at this distance visual competition between traps was small. When 16 suction traps were spaced 15 m apart in a grid of four columns of four traps each, the traps at the four corners of the grid captured about 2·1 times, and traps between the corner traps along the edge of the grid 1·5 times, as many mosquitoes of most species as traps within the grid. Subsequently, four additional traps were placed 15 m beyond the corner traps, and these traps captured 3·3 times as many mosquitoes as traps inside the grid. Traps within the grid had four adjacent traps while traps at the edge, corner, and beyond the corner had three, two and one adjacent traps, respectively. The numbers captured by a trap at a particular location in the grid were inversely related to the number of adjacent traps, viz., suction-trap catches were decreased by about 33% as the number of adjacent traps were increased and thus each trap acted as a competing visual attractant on nearby traps. It was estimated that an isolated suction trap would capture approximately five times as many mosquitoes as a trap inside the grid. Assuming these differences between trap collections were caused by the distance at which mosquitoes respond to the traps and thus would be proportional to the visually unobstructed area about each trap, it was calculated that most adults responded visually to the traps from distances of approximately 15·5 to 19 m. Aedes vexans (Mg.) and Psorophora columbiae (D. & K.) were most responsive, followed by Culex nigripalpus Theo. and Culiseta melanura (Coq.) and then by Anopheles crucians Wied., P. ciliata (F.) and Uranotaenia lowii Theo. Only U. sapphirina (O.S.) and Culex quinquefasciatus Say appeared to possess visual ranges of 7.5 m or less. Visually conspicuous objects can serve as long-distance attractants. Low air velocities caused appreciable reductions in trap collections. At a distance of 15 m, the velocity of air discharged from the traps was only 0·6 m/s, but catches from a trap downstream of an adjacent trap were reduced by 17%. Catches from rows of traps downstream from one, two or three rows of traps were reduced by 15, 36, and 51%, respectively. Estimates of mosquito population densities in a natural environment will be affected by the differing visual attractiveness of objects of irregular distribution and sizes and their effect upon wind velocities.